Merge pull request #1542 from katzyn/misc

Reduce GC pressure

h2/src/docsrc/html/changelog.html

@@ -21,6 +21,14 @@ Change Log
 
 <h2>Next Version (unreleased)</h2>
 <ul>
+<li>Issue #1534: Typo in message
+</li>
+<li>Issue #1527: Parser performance: Excessive use of regular expressions to validate column names
+</li>
+<li>PR #1543: MVStore assorted re-factorings
+</li>
+<li>PR #1538: Add support for newer Lucene versions without recompilation
+</li>
 <li>Issue #1536: CURRENT_TIMESTAMP result doesn't change under Transactions
 </li>
 <li>Issue #239: Consider supporting Lucene 5 indexes

h2/src/main/org/h2/api/Interval.java

@@ -628,7 +628,8 @@ public final class Interval {
 
     @Override
     public String toString() {
-        return IntervalUtils.intervalToString(qualifier, negative, leading, remaining);
+        return IntervalUtils.appendInterval(new StringBuilder(), getQualifier(), negative, leading, remaining)
+                .toString();
     }
 
 }

h2/src/main/org/h2/api/TimestampWithTimeZone.java

@@ -7,6 +7,7 @@ package org.h2.api;
 
 import java.io.Serializable;
 import org.h2.util.DateTimeUtils;
+import org.h2.value.ValueTimestampTimeZone;
 
 /**
  * How we expose "TIMESTAMP WITH TIME ZONE" in our ResultSets.
@@ -109,7 +110,9 @@ public class TimestampWithTimeZone implements Serializable, Cloneable {
 
     @Override
     public String toString() {
-        return DateTimeUtils.timestampTimeZoneToString(dateValue, timeNanos, timeZoneOffsetMins);
+        StringBuilder builder = new StringBuilder(ValueTimestampTimeZone.MAXIMUM_PRECISION);
+        DateTimeUtils.appendTimestampTimeZone(builder, dateValue, timeNanos, timeZoneOffsetMins);
+        return builder.toString();
     }
 
     @Override

h2/src/main/org/h2/command/Parser.java

@@ -2687,9 +2687,14 @@ public class Parser {
     }
 
     private void setSQL(Prepared command, String start, int startIndex) {
-        String sql = StringUtils.trimSubstring(originalSQL, startIndex, lastParseIndex);
+        int endIndex = lastParseIndex;
+        String sql;
         if (start != null) {
-            sql = start + " " + sql;
+            StringBuilder builder = new StringBuilder(start.length() + endIndex - startIndex + 1)
+                    .append(start).append(' ');
+            sql = StringUtils.trimSubstring(builder, originalSQL, startIndex, endIndex).toString();
+        } else {
+            sql = StringUtils.trimSubstring(originalSQL, startIndex, endIndex);
         }
         command.setSQL(sql);
     }
@@ -2743,16 +2748,13 @@ public class Parser {
             // special case: NOT NULL is not part of an expression (as in CREATE
             // TABLE TEST(ID INT DEFAULT 0 NOT NULL))
             int backup = parseIndex;
-            boolean not = false;
-            if (readIf(NOT)) {
-                not = true;
-                if (isToken(NULL)) {
-                    // this really only works for NOT NULL!
-                    parseIndex = backup;
-                    currentToken = "NOT";
-                    currentTokenType = NOT;
-                    break;
-                }
+            boolean not = readIf(NOT);
+            if (not && isToken(NULL)) {
+                // this really only works for NOT NULL!
+                parseIndex = backup;
+                currentToken = "NOT";
+                currentTokenType = NOT;
+                break;
             }
             if (readIf(LIKE)) {
                 Expression b = readConcat();
@@ -2841,6 +2843,9 @@ public class Parser {
                         Comparison.BIGGER_EQUAL, high, r);
                 r = new ConditionAndOr(ConditionAndOr.AND, condLow, condHigh);
             } else {
+                if (not) {
+                    throw getSyntaxError();
+                }
                 int compareType = getCompareType(currentTokenType);
                 if (compareType < 0) {
                     break;
@@ -4333,9 +4338,12 @@ public class Parser {
                 }
                 i++;
             }
-            currentToken = StringUtils.cache(sqlCommand.substring(
-                    start, i));
-            currentTokenType = getTokenType(currentToken);
+            currentTokenType = ParserUtil.getSaveTokenType(sqlCommand, !identifiersToUpper, start, i, false);
+            if (currentTokenType == IDENTIFIER) {
+                currentToken = StringUtils.cache(sqlCommand.substring(start, i));
+            } else {
+                currentToken = TOKENS[currentTokenType];
+            }
             parseIndex = i;
             return;
         case CHAR_QUOTED: {
@@ -4452,8 +4460,7 @@ public class Parser {
             }
             currentToken = "'";
             checkLiterals(true);
-            currentValue = ValueString.get(StringUtils.cache(result),
-                    database.getMode().treatEmptyStringsAsNull);
+            currentValue = ValueString.get(result, database.getMode().treatEmptyStringsAsNull);
             parseIndex = i;
             currentTokenType = VALUE;
             return;
@@ -4466,8 +4473,7 @@ public class Parser {
             String result = sqlCommand.substring(begin, i);
             currentToken = "'";
             checkLiterals(true);
-            currentValue = ValueString.get(StringUtils.cache(result),
-                    database.getMode().treatEmptyStringsAsNull);
+            currentValue = ValueString.get(result, database.getMode().treatEmptyStringsAsNull);
             parseIndex = i;
             currentTokenType = VALUE;
             return;
@@ -4891,18 +4897,6 @@ public class Parser {
         throw getSyntaxError();
     }
 
-    private int getTokenType(String s) {
-        int len = s.length();
-        if (len == 0) {
-            throw getSyntaxError();
-        }
-        if (!identifiersToUpper) {
-            // if not yet converted to uppercase, do it now
-            s = StringUtils.toUpperEnglish(s);
-        }
-        return ParserUtil.getSaveTokenType(s, false);
-    }
-
     private boolean isKeyword(String s) {
         if (!identifiersToUpper) {
             // if not yet converted to uppercase, do it now
@@ -7713,6 +7707,24 @@ public class Parser {
         return StringUtils.quoteIdentifier(s);
     }
 
+    /**
+     * Add double quotes around an identifier if required and appends it to the
+     * specified string builder.
+     *
+     * @param builder string builder to append to
+     * @param s the identifier
+     * @return the specified builder
+     */
+    public static StringBuilder quoteIdentifier(StringBuilder builder, String s) {
+        if (s == null) {
+            return builder.append("\"\"");
+        }
+        if (ParserUtil.isSimpleIdentifier(s)) {
+            return builder.append(s);
+        }
+        return StringUtils.quoteIdentifier(builder, s);
+    }
+
     public void setLiteralsChecked(boolean literalsChecked) {
         this.literalsChecked = literalsChecked;
     }

h2/src/main/org/h2/command/Prepared.java

@@ -405,7 +405,7 @@ public abstract class Prepared {
         for (Value v : values) {
             buff.appendExceptFirst(", ");
             if (v != null) {
-                buff.append(v.getSQL());
+                v.getSQL(buff.builder());
             }
         }
         return buff.toString();
@@ -418,14 +418,9 @@ public abstract class Prepared {
      * @return the SQL snippet
      */
     protected static String getSQL(Expression[] list) {
-        StatementBuilder buff = new StatementBuilder();
-        for (Expression e : list) {
-            buff.appendExceptFirst(", ");
-            if (e != null) {
-                buff.append(e.getSQL());
-            }
-        }
-        return buff.toString();
+        StringBuilder builder = new StringBuilder();
+        Expression.writeExpressions(builder, list);
+        return builder.toString();
     }
 
     /**

h2/src/main/org/h2/command/ddl/CreateUser.java

@@ -74,7 +74,7 @@ public class CreateUser extends DefineCommand {
         char[] passwordChars = pwd == null ? new char[0] : pwd.toCharArray();
         byte[] userPasswordHash;
         String userName = user.getName();
-        if (userName.length() == 0 && passwordChars.length == 0) {
+        if (userName.isEmpty() && passwordChars.length == 0) {
             userPasswordHash = new byte[0];
         } else {
             userPasswordHash = SHA256.getKeyPasswordHash(userName, passwordChars);

h2/src/main/org/h2/command/dml/Delete.java

@@ -20,7 +20,6 @@ import org.h2.result.RowList;
 import org.h2.table.PlanItem;
 import org.h2.table.Table;
 import org.h2.table.TableFilter;
-import org.h2.util.StringUtils;
 import org.h2.value.Value;
 import org.h2.value.ValueNull;
 
@@ -137,15 +136,15 @@ public class Delete extends Prepared {
     @Override
     public String getPlanSQL() {
         StringBuilder buff = new StringBuilder();
-        buff.append("DELETE ");
-        buff.append("FROM ").append(targetTableFilter.getPlanSQL(false));
+        buff.append("DELETE FROM ");
+        targetTableFilter.getPlanSQL(buff, false);
         if (condition != null) {
-            buff.append("\nWHERE ").append(StringUtils.unEnclose(
-                    condition.getSQL()));
+            buff.append("\nWHERE ");
+            condition.getUnenclosedSQL(buff);
         }
         if (limitExpr != null) {
-            buff.append("\nLIMIT (").append(StringUtils.unEnclose(
-                    limitExpr.getSQL())).append(')');
+            buff.append("\nLIMIT (");
+            limitExpr.getUnenclosedSQL(buff).append(')');
         }
         return buff.toString();
     }

h2/src/main/org/h2/command/dml/Insert.java

@@ -303,7 +303,7 @@ public class Insert extends Prepared implements ResultTarget {
                     if (e == null) {
                         buff.append("DEFAULT");
                     } else {
-                        buff.append(e.getSQL());
+                        e.getSQL(buff.builder());
                     }
                 }
                 buff.append(')');
@@ -421,7 +421,8 @@ public class Insert extends Prepared implements ResultTarget {
         for (Column column : duplicateKeyAssignmentMap.keySet()) {
             buff.appendExceptFirst(", ");
             Expression ex = duplicateKeyAssignmentMap.get(column);
-            buff.append(column.getSQL()).append('=').append(ex.getSQL());
+            buff.append(column.getSQL()).append('=');
+            ex.getSQL(buff.builder());
         }
         buff.append(" WHERE ");
         Index foundIndex = (Index) de.getSource();
@@ -429,7 +430,7 @@ public class Insert extends Prepared implements ResultTarget {
             throw DbException.getUnsupportedException(
                     "Unable to apply ON DUPLICATE KEY UPDATE, no index found!");
         }
-        buff.append(prepareUpdateCondition(foundIndex, row).getSQL());
+        prepareUpdateCondition(foundIndex, row).getSQL(buff.builder());
         String sql = buff.toString();
         Update command = (Update) session.prepare(sql);
         command.setUpdateToCurrentValuesReturnsZero(true);

h2/src/main/org/h2/command/dml/Merge.java

@@ -248,7 +248,7 @@ public class Merge extends Prepared {
                     if (e == null) {
                         buff.append("DEFAULT");
                     } else {
-                        buff.append(e.getSQL());
+                        e.getSQL(buff.builder());
                     }
                 }
                 buff.append(')');

h2/src/main/org/h2/command/dml/MergeUsing.java

@@ -25,7 +25,6 @@ import org.h2.result.Row;
 import org.h2.result.RowImpl;
 import org.h2.table.Table;
 import org.h2.table.TableFilter;
-import org.h2.util.StatementBuilder;
 import org.h2.util.Utils;
 import org.h2.value.Value;
 
@@ -343,10 +342,10 @@ public class MergeUsing extends Prepared {
 
     @Override
     public String getPlanSQL() {
-        StatementBuilder buff = new StatementBuilder("MERGE INTO ");
-        buff.append(targetTable.getSQL()).append('\n').append("USING ").append(query.getPlanSQL());
+        StringBuilder builder = new StringBuilder("MERGE INTO ");
+        builder.append(targetTable.getSQL()).append('\n').append("USING ").append(query.getPlanSQL());
         // TODO add aliases and WHEN clauses to make plan SQL more like original SQL
-        return buff.toString();
+        return builder.toString();
     }
 
     @Override

h2/src/main/org/h2/command/dml/Replace.java

@@ -228,7 +228,7 @@ public class Replace extends Prepared {
                     if (e == null) {
                         buff.append("DEFAULT");
                     } else {
-                        buff.append(e.getSQL());
+                        e.getSQL(buff.builder());
                     }
                 }
                 buff.append(')');

h2/src/main/org/h2/command/dml/ScriptCommand.java

@@ -392,7 +392,7 @@ public class ScriptCommand extends ScriptBase {
         buff.append(table.getSQL()).append('(');
         for (Column col : columns) {
             buff.appendExceptFirst(", ");
-            buff.append(Parser.quoteIdentifier(col.getName()));
+            Parser.quoteIdentifier(buff.builder(), col.getName());
         }
         buff.append(") VALUES");
         if (!simple) {
@@ -422,10 +422,10 @@ public class ScriptCommand extends ScriptBase {
                         id = writeLobStream(v);
                         buff.append("SYSTEM_COMBINE_BLOB(").append(id).append(')');
                     } else {
-                        buff.append(v.getSQL());
+                        v.getSQL(buff.builder());
                     }
                 } else {
-                    buff.append(v.getSQL());
+                    v.getSQL(buff.builder());
                 }
             }
             buff.append(')');
@@ -471,7 +471,7 @@ public class ScriptCommand extends ScriptBase {
                     if (len <= 0) {
                         break;
                     }
-                    buff.append(StringUtils.convertBytesToHex(bytes, len)).append("')");
+                    StringUtils.convertBytesToHex(buff, bytes, len).append("')");
                     String sql = buff.toString();
                     add(sql, true);
                 }
@@ -490,7 +490,7 @@ public class ScriptCommand extends ScriptBase {
                     if (len == 0) {
                         break;
                     }
-                    buff.append(StringUtils.quoteStringSQL(new String(chars, 0, len))).
+                    StringUtils.quoteStringSQL(buff, new String(chars, 0, len)).
                         append(", NULL)");
                     String sql = buff.toString();
                     add(sql, true);

h2/src/main/org/h2/command/dml/Select.java

@@ -1308,7 +1308,8 @@ public class Select extends Query {
                     // views.
                 } else {
                     buff.append("WITH RECURSIVE ")
-                            .append(t.getSchema().getSQL()).append('.').append(Parser.quoteIdentifier(t.getName()))
+                            .append(t.getSchema().getSQL()).append('.');
+                    Parser.quoteIdentifier(buff.builder(), t.getName())
                             .append('(');
                     buff.resetCount();
                     for (Column c : t.getColumns()) {
@@ -1327,7 +1328,7 @@ public class Select extends Query {
                 buff.append(" ON(");
                 for (Expression distinctExpression: distinctExpressions) {
                     buff.appendExceptFirst(", ");
-                    buff.append(distinctExpression.getSQL());
+                    distinctExpression.getSQL(buff.builder());
                 }
                 buff.append(')');
                 buff.resetCount();
@@ -1336,7 +1337,7 @@ public class Select extends Query {
         for (int i = 0; i < visibleColumnCount; i++) {
             buff.appendExceptFirst(",");
             buff.append('\n');
-            buff.append(StringUtils.indent(exprList[i].getSQL(), 4, false));
+            StringUtils.indent(buff.builder(), exprList[i].getSQL(), 4, false);
         }
         buff.append("\nFROM ");
         TableFilter filter = topTableFilter;
@@ -1345,7 +1346,7 @@ public class Select extends Query {
             int i = 0;
             do {
                 buff.appendExceptFirst("\n");
-                buff.append(filter.getPlanSQL(i++ > 0));
+                filter.getPlanSQL(buff.builder(), i++ > 0);
                 filter = filter.getJoin();
             } while (filter != null);
         } else {
@@ -1354,14 +1355,14 @@ public class Select extends Query {
             for (TableFilter f : topFilters) {
                 do {
                     buff.appendExceptFirst("\n");
-                    buff.append(f.getPlanSQL(i++ > 0));
+                    f.getPlanSQL(buff.builder(), i++ > 0);
                     f = f.getJoin();
                 } while (f != null);
             }
         }
         if (condition != null) {
-            buff.append("\nWHERE ").append(
-                    StringUtils.unEnclose(condition.getSQL()));
+            buff.append("\nWHERE ");
+            condition.getUnenclosedSQL(buff.builder());
         }
         if (groupIndex != null) {
             buff.append("\nGROUP BY ");
@@ -1370,7 +1371,7 @@ public class Select extends Query {
                 Expression g = exprList[gi];
                 g = g.getNonAliasExpression();
                 buff.appendExceptFirst(", ");
-                buff.append(StringUtils.unEnclose(g.getSQL()));
+                g.getUnenclosedSQL(buff.builder());
             }
         }
         if (group != null) {
@@ -1378,7 +1379,7 @@ public class Select extends Query {
             buff.resetCount();
             for (Expression g : group) {
                 buff.appendExceptFirst(", ");
-                buff.append(StringUtils.unEnclose(g.getSQL()));
+                g.getUnenclosedSQL(buff.builder());
             }
         }
         if (having != null) {
@@ -1386,12 +1387,12 @@ public class Select extends Query {
             // in this case the query is not run directly, just getPlanSQL is
             // called
             Expression h = having;
-            buff.append("\nHAVING ").append(
-                    StringUtils.unEnclose(h.getSQL()));
+            buff.append("\nHAVING ");
+            h.getUnenclosedSQL(buff.builder());
         } else if (havingIndex >= 0) {
             Expression h = exprList[havingIndex];
-            buff.append("\nHAVING ").append(
-                    StringUtils.unEnclose(h.getSQL()));
+            buff.append("\nHAVING ");
+            h.getUnenclosedSQL(buff.builder());
         }
         if (sort != null) {
             buff.append("\nORDER BY ").append(
@@ -1407,8 +1408,8 @@ public class Select extends Query {
         }
         appendLimitToSQL(buff.builder());
         if (sampleSizeExpr != null) {
-            buff.append("\nSAMPLE_SIZE ").append(
-                    StringUtils.unEnclose(sampleSizeExpr.getSQL()));
+            buff.append("\nSAMPLE_SIZE ");
+            sampleSizeExpr.getUnenclosedSQL(buff.builder());
         }
         if (isForUpdate) {
             buff.append("\nFOR UPDATE");

h2/src/main/org/h2/command/dml/SelectOrderBy.java

@@ -33,9 +33,10 @@ public class SelectOrderBy {
     public String getSQL() {
         StringBuilder buff = new StringBuilder();
         if (expression != null) {
-            buff.append('=').append(expression.getSQL());
+            buff.append('=');
+            expression.getSQL(buff);
         } else {
-            buff.append(columnIndexExpr.getSQL());
+            columnIndexExpr.getSQL(buff);
         }
         SortOrder.typeToString(buff, sortType);
         return buff.toString();

h2/src/main/org/h2/command/dml/SelectUnion.java

@@ -28,7 +28,6 @@ import org.h2.table.ColumnResolver;
 import org.h2.table.Table;
 import org.h2.table.TableFilter;
 import org.h2.util.ColumnNamer;
-import org.h2.util.StringUtils;
 import org.h2.value.Value;
 import org.h2.value.ValueInt;
 import org.h2.value.ValueNull;
@@ -429,8 +428,8 @@ public class SelectUnion extends Query {
         }
         appendLimitToSQL(buff);
         if (sampleSizeExpr != null) {
-            buff.append("\nSAMPLE_SIZE ").append(
-                    StringUtils.unEnclose(sampleSizeExpr.getSQL()));
+            buff.append("\nSAMPLE_SIZE ");
+            sampleSizeExpr.getUnenclosedSQL(buff);
         }
         if (isForUpdate) {
             buff.append("\nFOR UPDATE");

h2/src/main/org/h2/command/dml/Update.java

@@ -27,8 +27,6 @@ import org.h2.table.Column;
 import org.h2.table.PlanItem;
 import org.h2.table.Table;
 import org.h2.table.TableFilter;
-import org.h2.util.StatementBuilder;
-import org.h2.util.StringUtils;
 import org.h2.util.Utils;
 import org.h2.value.Value;
 import org.h2.value.ValueNull;
@@ -217,21 +215,25 @@ public class Update extends Prepared {
 
     @Override
     public String getPlanSQL() {
-        StatementBuilder buff = new StatementBuilder("UPDATE ");
-        buff.append(targetTableFilter.getPlanSQL(false)).append("\nSET\n    ");
-        for (Column c : columns) {
-            Expression e = expressionMap.get(c);
-            buff.appendExceptFirst(",\n    ");
-            buff.append(c.getName()).append(" = ").append(e.getSQL());
+        StringBuilder builder = new StringBuilder("UPDATE ");
+        targetTableFilter.getPlanSQL(builder, false).append("\nSET\n    ");
+        for (int i = 0, size = columns.size(); i < size; i++) {
+            if (i > 0) {
+                builder.append(",\n    ");
+            }
+            Column c = columns.get(i);
+            builder.append(c.getName()).append(" = ");
+            expressionMap.get(c).getSQL(builder);
         }
         if (condition != null) {
-            buff.append("\nWHERE ").append(StringUtils.unEnclose(condition.getSQL()));
+            builder.append("\nWHERE ");
+            condition.getUnenclosedSQL(builder);
         }
         if (limitExpr != null) {
-            buff.append("\nLIMIT ").append(
-                    StringUtils.unEnclose(limitExpr.getSQL()));
+            builder.append("\nLIMIT ");
+            limitExpr.getUnenclosedSQL(builder);
         }
-        return buff.toString();
+        return builder.toString();
     }
 
     @Override

h2/src/main/org/h2/constraint/ConstraintCheck.java

@@ -56,15 +56,18 @@ public class ConstraintCheck extends Constraint {
         }
         buff.append(quotedName);
         if (comment != null) {
-            buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
+            buff.append(" COMMENT ");
+            StringUtils.quoteStringSQL(buff, comment);
         }
-        buff.append(" CHECK").append(StringUtils.enclose(expr.getSQL()))
-                .append(" NOCHECK");
+        buff.append(" CHECK(");
+        expr.getUnenclosedSQL(buff).append(") NOCHECK");
         return buff.toString();
     }
 
     private String getShortDescription() {
-        return getName() + ": " + expr.getSQL();
+        StringBuilder builder = new StringBuilder().append(getName()).append(": ");
+        expr.getSQL(builder);
+        return builder.toString();
     }
 
     @Override
@@ -140,8 +143,11 @@ public class ConstraintCheck extends Constraint {
             // don't check at startup
             return;
         }
-        String sql = "SELECT 1 FROM " + filter.getTable().getSQL() +
-                " WHERE NOT(" + expr.getSQL() + ")";
+        StringBuilder builder = new StringBuilder().append("SELECT 1 FROM ")
+                .append(filter.getTable().getSQL())
+                .append(" WHERE NOT(");
+        expr.getSQL(builder).append(')');
+        String sql = builder.toString();
         ResultInterface r = session.prepare(sql).query(1);
         if (r.next()) {
             throw DbException.get(ErrorCode.CHECK_CONSTRAINT_VIOLATED_1, getName());

h2/src/main/org/h2/constraint/ConstraintReferential.java

@@ -87,7 +87,8 @@ public class ConstraintReferential extends Constraint {
         }
         buff.append(quotedName);
         if (comment != null) {
-            buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
+            buff.append(" COMMENT ");
+            StringUtils.quoteStringSQL(buff.builder(), comment);
         }
         IndexColumn[] cols = columns;
         IndexColumn[] refCols = refColumns;
@@ -566,8 +567,8 @@ public class ConstraintReferential extends Constraint {
         buff.append("UPDATE ").append(table.getSQL()).append(" SET ");
         buff.resetCount();
         for (IndexColumn c : columns) {
-            buff.appendExceptFirst(" , ");
-            buff.append(Parser.quoteIdentifier(c.column.getName())).append("=?");
+            buff.appendExceptFirst(", ");
+            Parser.quoteIdentifier(buff.builder(), c.column.getName()).append("=?");
         }
     }
 
@@ -576,7 +577,7 @@ public class ConstraintReferential extends Constraint {
         buff.resetCount();
         for (IndexColumn c : columns) {
             buff.appendExceptFirst(" AND ");
-            buff.append(Parser.quoteIdentifier(c.column.getName())).append("=?");
+            Parser.quoteIdentifier(buff.builder(), c.column.getName()).append("=?");
         }
     }
 

h2/src/main/org/h2/constraint/ConstraintUnique.java

@@ -52,12 +52,13 @@ public class ConstraintUnique extends Constraint {
         }
         buff.append(quotedName);
         if (comment != null) {
-            buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
+            buff.append(" COMMENT ");
+            StringUtils.quoteStringSQL(buff.builder(), comment);
         }
         buff.append(' ').append(getConstraintType().getSqlName()).append('(');
         for (IndexColumn c : columns) {
             buff.appendExceptFirst(", ");
-            buff.append(Parser.quoteIdentifier(c.column.getName()));
+            Parser.quoteIdentifier(buff.builder(), c.column.getName());
         }
         buff.append(')');
         if (internalIndex && indexOwner && forTable == this.table) {

h2/src/main/org/h2/engine/Comment.java

@@ -74,7 +74,7 @@ public class Comment extends DbObjectBase {
         if (commentText == null) {
             buff.append("NULL");
         } else {
-            buff.append(StringUtils.quoteStringSQL(commentText));
+            StringUtils.quoteStringSQL(buff, commentText);
         }
         return buff.toString();
     }

h2/src/main/org/h2/engine/ConnectionInfo.java

@@ -252,7 +252,7 @@ public class ConnectionInfo implements Cloneable {
             url = url.substring(0, idx);
             String[] list = StringUtils.arraySplit(settings, ';', false);
             for (String setting : list) {
-                if (setting.length() == 0) {
+                if (setting.isEmpty()) {
                     continue;
                 }
                 int equal = setting.indexOf('=');
@@ -326,7 +326,7 @@ public class ConnectionInfo implements Cloneable {
         if (passwordHash) {
             return StringUtils.convertHexToBytes(new String(password));
         }
-        if (userName.length() == 0 && password.length == 0) {
+        if (userName.isEmpty() && password.length == 0) {
             return new byte[0];
         }
         return SHA256.getKeyPasswordHash(userName, password);
@@ -643,7 +643,7 @@ public class ConnectionInfo implements Cloneable {
 
     private static String remapURL(String url) {
         String urlMap = SysProperties.URL_MAP;
-        if (urlMap != null && urlMap.length() > 0) {
+        if (urlMap != null && !urlMap.isEmpty()) {
             try {
                 SortedProperties prop;
                 prop = SortedProperties.loadProperties(urlMap);
@@ -653,7 +653,7 @@ public class ConnectionInfo implements Cloneable {
                     prop.store(urlMap);
                 } else {
                     url2 = url2.trim();
-                    if (url2.length() > 0) {
+                    if (!url2.isEmpty()) {
                         return url2;
                     }
                 }

h2/src/main/org/h2/engine/Database.java

@@ -642,7 +642,7 @@ public class Database implements DataHandler {
                 n = tokenizer.nextToken();
             }
         }
-        if (n == null || n.length() == 0) {
+        if (n == null || n.isEmpty()) {
             n = "unnamed";
         }
         return dbSettings.databaseToUpper ? StringUtils.toUpperEnglish(n) : n;
@@ -2274,7 +2274,7 @@ public class Database implements DataHandler {
     }
 
     public void setEventListenerClass(String className) {
-        if (className == null || className.length() == 0) {
+        if (className == null || className.isEmpty()) {
             eventListener = null;
         } else {
             try {

h2/src/main/org/h2/engine/FunctionAlias.java

@@ -223,10 +223,11 @@ public class FunctionAlias extends SchemaObjectBase {
             buff.append(" NOBUFFER");
         }
         if (source != null) {
-            buff.append(" AS ").append(StringUtils.quoteStringSQL(source));
+            buff.append(" AS ");
+            StringUtils.quoteStringSQL(buff, source);
         } else {
-            buff.append(" FOR ").append(Parser.quoteIdentifier(
-                    className + "." + methodName));
+            buff.append(" FOR ");
+            Parser.quoteIdentifier(buff, className + "." + methodName);
         }
         return buff.toString();
     }

h2/src/main/org/h2/engine/User.java

@@ -159,13 +159,14 @@ public class User extends RightOwner {
         StringBuilder buff = new StringBuilder("CREATE USER IF NOT EXISTS ");
         buff.append(getSQL());
         if (comment != null) {
-            buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
+            buff.append(" COMMENT ");
+            StringUtils.quoteStringSQL(buff, comment);
         }
         if (password) {
-            buff.append(" SALT '").
-                append(StringUtils.convertBytesToHex(salt)).
-                append("' HASH '").
-                append(StringUtils.convertBytesToHex(passwordHash)).
+            buff.append(" SALT '");
+            StringUtils.convertBytesToHex(buff, salt).
+                append("' HASH '");
+            StringUtils.convertBytesToHex(buff, passwordHash).
                 append('\'');
         } else {
             buff.append(" PASSWORD ''");

h2/src/main/org/h2/expression/Alias.java

@@ -78,8 +78,9 @@ public class Alias extends Expression {
     }
 
     @Override
-    public String getSQL() {
-        return expr.getSQL() + " AS " + Parser.quoteIdentifier(alias);
+    public StringBuilder getSQL(StringBuilder builder) {
+        expr.getSQL(builder).append(" AS ");
+        return Parser.quoteIdentifier(builder, alias);
     }
 
     @Override

h2/src/main/org/h2/expression/BinaryOperation.java

@@ -68,10 +68,12 @@ public class BinaryOperation extends Expression {
     }
 
     @Override
-    public String getSQL() {
+    public StringBuilder getSQL(StringBuilder builder) {
         // don't remove the space, otherwise it might end up some thing like
         // --1 which is a line remark
-        return '(' + left.getSQL() + ' ' + getOperationToken() + ' ' + right.getSQL() + ')';
+        builder.append('(');
+        left.getSQL(builder).append(' ').append(getOperationToken()).append(' ');
+        return right.getSQL(builder).append(')');
     }
 
     private String getOperationToken() {

h2/src/main/org/h2/expression/CompareLike.java

@@ -72,21 +72,24 @@ public class CompareLike extends Condition {
     }
 
     private static Character getEscapeChar(String s) {
-        return s == null || s.length() == 0 ? null : s.charAt(0);
+        return s == null || s.isEmpty() ? null : s.charAt(0);
     }
 
     @Override
-    public String getSQL() {
-        String sql;
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('(');
         if (regexp) {
-            sql = left.getSQL() + " REGEXP " + right.getSQL();
+            left.getSQL(builder).append(" REGEXP ");
+            right.getSQL(builder);
         } else {
-            sql = left.getSQL() + " LIKE " + right.getSQL();
+            left.getSQL(builder).append(" LIKE ");
+            right.getSQL(builder);
             if (escape != null) {
-                sql += " ESCAPE " + escape.getSQL();
+                builder.append(" ESCAPE ");
+                escape.getSQL(builder);
             }
         }
-        return "(" + sql + ")";
+        return builder.append(')');
     }
 
     @Override

h2/src/main/org/h2/expression/Comparison.java

@@ -126,23 +126,25 @@ public class Comparison extends Condition {
     }
 
     @Override
-    public String getSQL() {
-        String sql;
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('(');
         switch (compareType) {
         case IS_NULL:
-            sql = left.getSQL() + " IS NULL";
+            left.getSQL(builder).append(" IS NULL");
             break;
         case IS_NOT_NULL:
-            sql = left.getSQL() + " IS NOT NULL";
+            left.getSQL(builder).append(" IS NOT NULL");
             break;
         case SPATIAL_INTERSECTS:
-            sql = "INTERSECTS(" + left.getSQL() + ", " + right.getSQL() + ")";
+            builder.append("INTERSECTS(");
+            left.getSQL(builder).append(", ");
+            right.getSQL(builder).append(')');
             break;
         default:
-            sql = left.getSQL() + " " + getCompareOperator(compareType) +
-                    " " + right.getSQL();
+            left.getSQL(builder).append(' ').append(getCompareOperator(compareType)).append(' ');
+            right.getSQL(builder);
         }
-        return "(" + sql + ")";
+        return builder.append(')');
     }
 
     /**

h2/src/main/org/h2/expression/ConditionAndOr.java

@@ -42,19 +42,20 @@ public class ConditionAndOr extends Condition {
     }
 
     @Override
-    public String getSQL() {
-        String sql;
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('(');
+        left.getSQL(builder);
         switch (andOrType) {
         case AND:
-            sql = left.getSQL() + "\n    AND " + right.getSQL();
+            builder.append("\n    AND ");
             break;
         case OR:
-            sql = left.getSQL() + "\n    OR " + right.getSQL();
+            builder.append("\n    OR ");
             break;
         default:
             throw DbException.throwInternalError("andOrType=" + andOrType);
         }
-        return "(" + sql + ")";
+        return right.getSQL(builder).append(')');
     }
 
     @Override

h2/src/main/org/h2/expression/ConditionExists.java

@@ -41,8 +41,9 @@ public class ConditionExists extends Condition {
     }
 
     @Override
-    public String getSQL() {
-        return "EXISTS(\n" + StringUtils.indent(query.getPlanSQL(), 4, false) + ")";
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append("EXISTS(\n");
+        return StringUtils.indent(builder, query.getPlanSQL(), 4, false).append(')');
     }
 
     @Override

h2/src/main/org/h2/expression/ConditionIn.java

@@ -11,7 +11,6 @@ import org.h2.engine.Session;
 import org.h2.index.IndexCondition;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
-import org.h2.util.StatementBuilder;
 import org.h2.value.Value;
 import org.h2.value.ValueBoolean;
 import org.h2.value.ValueNull;
@@ -152,14 +151,11 @@ public class ConditionIn extends Condition {
     }
 
     @Override
-    public String getSQL() {
-        StatementBuilder buff = new StatementBuilder("(");
-        buff.append(left.getSQL()).append(" IN(");
-        for (Expression e : valueList) {
-            buff.appendExceptFirst(", ");
-            buff.append(e.getSQL());
-        }
-        return buff.append("))").toString();
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('(');
+        left.getSQL(builder).append(" IN(");
+        writeExpressions(builder, valueList);
+        return builder.append("))");
     }
 
     @Override

h2/src/main/org/h2/expression/ConditionInConstantSet.java

@@ -15,7 +15,6 @@ import org.h2.index.IndexCondition;
 import org.h2.message.DbException;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
-import org.h2.util.StatementBuilder;
 import org.h2.value.ExtTypeInfo;
 import org.h2.value.Value;
 import org.h2.value.ValueBoolean;
@@ -114,14 +113,11 @@ public class ConditionInConstantSet extends Condition {
     }
 
     @Override
-    public String getSQL() {
-        StatementBuilder buff = new StatementBuilder("(");
-        buff.append(left.getSQL()).append(" IN(");
-        for (Expression e : valueList) {
-            buff.appendExceptFirst(", ");
-            buff.append(e.getSQL());
-        }
-        return buff.append("))").toString();
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('(');
+        left.getSQL(builder).append(" IN(");
+        writeExpressions(builder, valueList);
+        return builder.append("))");
     }
 
     @Override

h2/src/main/org/h2/expression/ConditionInParameter.java

@@ -140,8 +140,10 @@ public class ConditionInParameter extends Condition {
     }
 
     @Override
-    public String getSQL() {
-        return '(' + left.getSQL() + " = ANY(" + parameter.getSQL() + "))";
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('(');
+        left.getSQL(builder).append(" = ANY(");
+        return parameter.getSQL(builder).append("))");
     }
 
     @Override

h2/src/main/org/h2/expression/ConditionInSelect.java

@@ -129,23 +129,22 @@ public class ConditionInSelect extends Condition {
     }
 
     @Override
-    public String getSQL() {
-        StringBuilder buff = new StringBuilder();
-        buff.append('(').append(left.getSQL()).append(' ');
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('(');
+        left.getSQL(builder).append(' ');
         if (all) {
-            buff.append(Comparison.getCompareOperator(compareType)).
+            builder.append(Comparison.getCompareOperator(compareType)).
                 append(" ALL");
         } else {
             if (compareType == Comparison.EQUAL) {
-                buff.append("IN");
+                builder.append("IN");
             } else {
-                buff.append(Comparison.getCompareOperator(compareType)).
+                builder.append(Comparison.getCompareOperator(compareType)).
                     append(" ANY");
             }
         }
-        buff.append("(\n").append(StringUtils.indent(query.getPlanSQL(), 4, false)).
-            append("))");
-        return buff.toString();
+        builder.append("(\n");
+        return StringUtils.indent(builder, query.getPlanSQL(), 4, false).append("))");
     }
 
     @Override

h2/src/main/org/h2/expression/ConditionNot.java

@@ -65,8 +65,9 @@ public class ConditionNot extends Condition {
     }
 
     @Override
-    public String getSQL() {
-        return "(NOT " + condition.getSQL() + ")";
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append("(NOT ");
+        return condition.getSQL(builder).append(')');
     }
 
     @Override

h2/src/main/org/h2/expression/Expression.java

@@ -5,13 +5,14 @@
  */
 package org.h2.expression;
 
+import java.util.List;
+
 import org.h2.engine.Database;
 import org.h2.engine.Session;
 import org.h2.result.ResultInterface;
 import org.h2.table.Column;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
-import org.h2.util.StringUtils;
 import org.h2.value.Value;
 import org.h2.value.ValueArray;
 
@@ -39,6 +40,24 @@ public abstract class Expression {
 
     private boolean addedToFilter;
 
+    public static void writeExpressions(StringBuilder builder, List<? extends Expression> expressions) {
+        for (int i = 0, length = expressions.size(); i < length; i++) {
+            if (i > 0) {
+                builder.append(", ");
+            }
+            expressions.get(i).getSQL(builder);
+        }
+    }
+
+    public static void writeExpressions(StringBuilder builder, Expression[] expressions) {
+        for (int i = 0, length = expressions.length; i < length; i++) {
+            if (i > 0) {
+                builder.append(", ");
+            }
+            expressions[i].getSQL(builder);
+        }
+    }
+
     /**
      * Return the resulting value for the current row.
      *
@@ -110,7 +129,39 @@ public abstract class Expression {
      *
      * @return the SQL statement
      */
-    public abstract String getSQL();
+    public String getSQL() {
+        return getSQL(new StringBuilder()).toString();
+    }
+
+    /**
+     * Appends the SQL statement of this expression to the specified builder.
+     * This may not always be the original SQL statement, specially after
+     * optimization.
+     *
+     * @param builder
+     *            string builder
+     * @return the specified string builder
+     */
+    public abstract StringBuilder getSQL(StringBuilder builder);
+
+    /**
+     * Appends the SQL statement of this expression to the specified builder.
+     * This may not always be the original SQL statement, specially after
+     * optimization. Enclosing '(' and ')' are removed.
+     *
+     * @param builder
+     *            string builder
+     * @return the specified string builder
+     */
+    public StringBuilder getUnenclosedSQL(StringBuilder builder) {
+        int first = builder.length();
+        int last = getSQL(builder).length() - 1;
+        if (last > first && builder.charAt(first) == '(' && builder.charAt(last) == ')') {
+            builder.setLength(last);
+            builder.deleteCharAt(first);
+        }
+        return builder;
+    }
 
     /**
      * Update an aggregate value. This method is called at statement execution
@@ -268,7 +319,7 @@ public abstract class Expression {
      * @return the alias name
      */
     public String getAlias() {
-        return StringUtils.unEnclose(getSQL());
+        return getUnenclosedSQL(new StringBuilder()).toString();
     }
 
     /**

h2/src/main/org/h2/expression/ExpressionColumn.java

@@ -55,23 +55,32 @@ public class ExpressionColumn extends Expression {
     }
 
     @Override
-    public String getSQL() {
-        String sql;
+    public StringBuilder getSQL(StringBuilder builder) {
         boolean quote = database.getSettings().databaseToUpper;
-        if (column != null) {
-            sql = column.getSQL();
-        } else {
-            sql = quote ? Parser.quoteIdentifier(columnName) : columnName;
+        if (schemaName != null) {
+            if (quote) {
+                Parser.quoteIdentifier(builder, schemaName);
+            } else {
+                builder.append(schemaName);
+            }
+            builder.append('.');
         }
         if (tableAlias != null) {
-            String a = quote ? Parser.quoteIdentifier(tableAlias) : tableAlias;
-            sql = a + "." + sql;
+            if (quote) {
+                Parser.quoteIdentifier(builder, tableAlias);
+            } else {
+                builder.append(tableAlias);
+            }
+            builder.append('.');
         }
-        if (schemaName != null) {
-            String s = quote ? Parser.quoteIdentifier(schemaName) : schemaName;
-            sql = s + "." + sql;
+        if (column != null) {
+            builder.append(column.getSQL());
+        } else if (quote) {
+            Parser.quoteIdentifier(builder, columnName);
+        } else {
+            builder.append(columnName);
         }
-        return sql;
+        return builder;
     }
 
     public TableFilter getTableFilter() {

h2/src/main/org/h2/expression/ExpressionList.java

@@ -9,7 +9,6 @@ import org.h2.engine.Session;
 import org.h2.table.Column;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
-import org.h2.util.StatementBuilder;
 import org.h2.value.Value;
 import org.h2.value.ValueArray;
 
@@ -85,16 +84,13 @@ public class ExpressionList extends Expression {
     }
 
     @Override
-    public String getSQL() {
-        StatementBuilder buff = new StatementBuilder("(");
-        for (Expression e: list) {
-            buff.appendExceptFirst(", ");
-            buff.append(e.getSQL());
-        }
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('(');
+        writeExpressions(builder, list);
         if (list.length == 1) {
-            buff.append(',');
+            builder.append(',');
         }
-        return buff.append(')').toString();
+        return builder.append(')');
     }
 
     @Override

h2/src/main/org/h2/expression/Function.java

@@ -50,7 +50,6 @@ import org.h2.util.DateTimeUtils;
 import org.h2.util.IOUtils;
 import org.h2.util.JdbcUtils;
 import org.h2.util.MathUtils;
-import org.h2.util.StatementBuilder;
 import org.h2.util.StringUtils;
 import org.h2.util.ToChar;
 import org.h2.util.ToDateParser;
@@ -682,7 +681,7 @@ public class Function extends Expression implements FunctionCall {
             // string
         case ASCII: {
             String s = v0.getString();
-            if (s.length() == 0) {
+            if (s.isEmpty()) {
                 result = ValueNull.INSTANCE;
             } else {
                 result = ValueInt.get(s.charAt(0));
@@ -2582,36 +2581,41 @@ public class Function extends Expression implements FunctionCall {
     }
 
     @Override
-    public String getSQL() {
-        StatementBuilder buff = new StatementBuilder(info.name);
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append(info.name);
         if (info.type == CASE) {
             if (args[0] != null) {
-                buff.append(' ').append(args[0].getSQL());
+                builder.append(' ');
+                args[0].getSQL(builder);
             }
             for (int i = 1, len = args.length - 1; i < len; i += 2) {
-                buff.append(" WHEN ").append(args[i].getSQL());
-                buff.append(" THEN ").append(args[i + 1].getSQL());
+                builder.append(" WHEN ");
+                args[i].getSQL(builder);
+                builder.append(" THEN ");
+                args[i + 1].getSQL(builder);
             }
             if (args.length % 2 == 0) {
-                buff.append(" ELSE ").append(args[args.length - 1].getSQL());
+                builder.append(" ELSE ");
+                args[args.length - 1].getSQL(builder);
             }
-            return buff.append(" END").toString();
+            return builder.append(" END");
         }
-        buff.append('(');
+        builder.append('(');
         switch (info.type) {
         case CAST: {
-            buff.append(args[0].getSQL()).append(" AS ").
+            args[0].getSQL(builder).append(" AS ").
                 append(new Column(null, dataType, precision,
                         scale, displaySize, extTypeInfo).getCreateSQL());
             break;
         }
         case CONVERT: {
             if (database.getMode().swapConvertFunctionParameters) {
-                buff.append(new Column(null, dataType, precision,
+                builder.append(new Column(null, dataType, precision,
                         scale, displaySize).getCreateSQL()).
-                    append(',').append(args[0].getSQL());
+                    append(',');
+                args[0].getSQL(builder);
             } else {
-                buff.append(args[0].getSQL()).append(',').
+                args[0].getSQL(builder).append(',').
                     append(new Column(null, dataType, precision,
                         scale, displaySize).getCreateSQL());
             }
@@ -2619,17 +2623,14 @@ public class Function extends Expression implements FunctionCall {
         }
         case EXTRACT: {
             ValueString v = (ValueString) ((ValueExpression) args[0]).getValue(null);
-            buff.append(v.getString()).append(" FROM ").append(args[1].getSQL());
+            builder.append(v.getString()).append(" FROM ");
+            args[1].getSQL(builder);
             break;
         }
-        default: {
-            for (Expression e : args) {
-                buff.appendExceptFirst(", ");
-                buff.append(e.getSQL());
-            }
-        }
+        default:
+            writeExpressions(builder, args);
         }
-        return buff.append(')').toString();
+        return builder.append(')');
     }
 
     @Override
@@ -2703,19 +2704,17 @@ public class Function extends Expression implements FunctionCall {
             String fieldDelimiter, String escapeCharacter) {
         if (fieldSeparator != null) {
             csv.setFieldSeparatorWrite(fieldSeparator);
-            if (fieldSeparator.length() > 0) {
+            if (!fieldSeparator.isEmpty()) {
                 char fs = fieldSeparator.charAt(0);
                 csv.setFieldSeparatorRead(fs);
             }
         }
         if (fieldDelimiter != null) {
-            char fd = fieldDelimiter.length() == 0 ?
-                    0 : fieldDelimiter.charAt(0);
+            char fd = fieldDelimiter.isEmpty() ? 0 : fieldDelimiter.charAt(0);
             csv.setFieldDelimiter(fd);
         }
         if (escapeCharacter != null) {
-            char ec = escapeCharacter.length() == 0 ?
-                    0 : escapeCharacter.charAt(0);
+            char ec = escapeCharacter.isEmpty() ? 0 : escapeCharacter.charAt(0);
             csv.setEscapeCharacter(ec);
         }
     }

h2/src/main/org/h2/expression/IntervalOperation.java

@@ -113,8 +113,10 @@ public class IntervalOperation extends Expression {
     }
 
     @Override
-    public String getSQL() {
-        return '(' + left.getSQL() + ' ' + getOperationToken() + ' ' + right.getSQL() + ')';
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('(');
+        left.getSQL(builder).append(' ').append(getOperationToken()).append(' ');
+        return right.getSQL(builder).append(')');
     }
 
     private char getOperationToken() {

h2/src/main/org/h2/expression/JavaFunction.java

@@ -11,7 +11,6 @@ import org.h2.engine.FunctionAlias;
 import org.h2.engine.Session;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
-import org.h2.util.StatementBuilder;
 import org.h2.value.DataType;
 import org.h2.value.Value;
 import org.h2.value.ValueArray;
@@ -89,21 +88,15 @@ public class JavaFunction extends Expression implements FunctionCall {
     }
 
     @Override
-    public String getSQL() {
-        StatementBuilder buff = new StatementBuilder();
+    public StringBuilder getSQL(StringBuilder builder) {
         // TODO always append the schema once FUNCTIONS_IN_SCHEMA is enabled
         if (functionAlias.getDatabase().getSettings().functionsInSchema ||
                 !functionAlias.getSchema().getName().equals(Constants.SCHEMA_MAIN)) {
-            buff.append(
-                    Parser.quoteIdentifier(functionAlias.getSchema().getName()))
-                    .append('.');
+            Parser.quoteIdentifier(builder, functionAlias.getSchema().getName()).append('.');
         }
-        buff.append(Parser.quoteIdentifier(functionAlias.getName())).append('(');
-        for (Expression e : args) {
-            buff.appendExceptFirst(", ");
-            buff.append(e.getSQL());
-        }
-        return buff.append(')').toString();
+        Parser.quoteIdentifier(builder, functionAlias.getName()).append('(');
+        writeExpressions(builder, this.args);
+        return builder.append(')');
     }
 
     @Override

h2/src/main/org/h2/expression/Parameter.java

@@ -30,8 +30,8 @@ public class Parameter extends Expression implements ParameterInterface {
     }
 
     @Override
-    public String getSQL() {
-        return "?" + (index + 1);
+    public StringBuilder getSQL(StringBuilder builder) {
+        return builder.append('?').append(index + 1);
     }
 
     @Override

h2/src/main/org/h2/expression/Rownum.java

@@ -72,6 +72,11 @@ public class Rownum extends Expression {
         return "ROWNUM()";
     }
 
+    @Override
+    public StringBuilder getSQL(StringBuilder builder) {
+        return builder.append("ROWNUM()");
+    }
+
     @Override
     public void updateAggregate(Session session, int stage) {
         // nothing to do

h2/src/main/org/h2/expression/SequenceValue.java

@@ -67,8 +67,9 @@ public class SequenceValue extends Expression {
     }
 
     @Override
-    public String getSQL() {
-        return "(NEXT VALUE FOR " + sequence.getSQL() +")";
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append("(NEXT VALUE FOR ");
+        return builder.append(sequence.getSQL()).append(')');
     }
 
     @Override

h2/src/main/org/h2/expression/Subquery.java

@@ -89,8 +89,8 @@ public class Subquery extends Expression {
     }
 
     @Override
-    public String getSQL() {
-        return "(" + query.getPlanSQL() + ")";
+    public StringBuilder getSQL(StringBuilder builder) {
+        return builder.append('(').append(query.getPlanSQL()).append(')');
     }
 
     @Override

h2/src/main/org/h2/expression/TableFunction.java

@@ -13,7 +13,6 @@ import org.h2.engine.Session;
 import org.h2.message.DbException;
 import org.h2.result.LocalResult;
 import org.h2.table.Column;
-import org.h2.util.StatementBuilder;
 import org.h2.value.Value;
 import org.h2.value.ValueArray;
 import org.h2.value.ValueNull;
@@ -46,15 +45,16 @@ public class TableFunction extends Function {
     }
 
     @Override
-    public String getSQL() {
-        StatementBuilder buff = new StatementBuilder(getName());
-        buff.append('(');
-        int i = 0;
-        for (Expression e : args) {
-            buff.appendExceptFirst(", ");
-            buff.append(columnList[i++].getCreateSQL()).append('=').append(e.getSQL());
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append(getName()).append('(');
+        for (int i = 0; i < args.length; i++) {
+            if (i > 0) {
+                builder.append(", ");
+            }
+            builder.append(columnList[i].getCreateSQL()).append('=');
+            args[i].getSQL(builder);
         }
-        return buff.append(')').toString();
+        return builder.append(')');
     }
 
 

h2/src/main/org/h2/expression/UnaryOperation.java

@@ -24,10 +24,11 @@ public class UnaryOperation extends Expression {
     }
 
     @Override
-    public String getSQL() {
+    public StringBuilder getSQL(StringBuilder builder) {
         // don't remove the space, otherwise it might end up some thing like
         // --1 which is a line remark
-        return "(- " + arg.getSQL() + ')';
+        builder.append("(- ");
+        return arg.getSQL(builder).append(')');
     }
 
     @Override

h2/src/main/org/h2/expression/ValueExpression.java

@@ -135,11 +135,13 @@ public class ValueExpression extends Expression {
     }
 
     @Override
-    public String getSQL() {
+    public StringBuilder getSQL(StringBuilder builder) {
         if (this == DEFAULT) {
-            return "DEFAULT";
+            builder.append("DEFAULT");
+        } else {
+            value.getSQL(builder);
         }
-        return value.getSQL();
+        return builder;
     }
 
     @Override

h2/src/main/org/h2/expression/Variable.java

@@ -41,8 +41,9 @@ public class Variable extends Expression {
     }
 
     @Override
-    public String getSQL() {
-        return "@" + Parser.quoteIdentifier(name);
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append('@');
+        return Parser.quoteIdentifier(builder, name);
     }
 
     @Override

h2/src/main/org/h2/expression/Wildcard.java

@@ -116,24 +116,17 @@ public class Wildcard extends Expression {
     }
 
     @Override
-    public String getSQL() {
-        StringBuilder builder = new StringBuilder();
+    public StringBuilder getSQL(StringBuilder builder) {
         if (table != null) {
-            builder.append(StringUtils.quoteIdentifier(table)).append('.');
+            StringUtils.quoteIdentifier(builder, table).append('.');
         }
         builder.append('*');
         if (exceptColumns != null) {
             builder.append(" EXCEPT (");
-            for (int i = 0; i < exceptColumns.size(); i++) {
-                if (i > 0) {
-                    builder.append(", ");
-                }
-                ExpressionColumn ec = exceptColumns.get(i);
-                builder.append(ec.getSQL());
-            }
+            writeExpressions(builder, exceptColumns);
             builder.append(')');
         }
-        return builder.toString();
+        return builder;
     }
 
     @Override

h2/src/main/org/h2/expression/aggregate/AbstractAggregate.java

@@ -159,7 +159,8 @@ public abstract class AbstractAggregate extends DataAnalysisOperation {
     @Override
     protected StringBuilder appendTailConditions(StringBuilder builder) {
         if (filterCondition != null) {
-            builder.append(" FILTER (WHERE ").append(filterCondition.getSQL()).append(')');
+            builder.append(" FILTER (WHERE ");
+            filterCondition.getSQL(builder).append(')');
         }
         return super.appendTailConditions(builder);
     }

h2/src/main/org/h2/expression/aggregate/Aggregate.java

@@ -30,7 +30,6 @@ import org.h2.table.ColumnResolver;
 import org.h2.table.Table;
 import org.h2.table.TableFilter;
 import org.h2.util.StatementBuilder;
-import org.h2.util.StringUtils;
 import org.h2.util.ValueHashMap;
 import org.h2.value.CompareMode;
 import org.h2.value.DataType;
@@ -729,39 +728,40 @@ public class Aggregate extends AbstractAggregate {
         return displaySize;
     }
 
-    private String getSQLGroupConcat() {
-        StringBuilder buff = new StringBuilder("GROUP_CONCAT(");
+    private StringBuilder getSQLGroupConcat(StringBuilder builder) {
+        builder.append("GROUP_CONCAT(");
         if (distinct) {
-            buff.append("DISTINCT ");
+            builder.append("DISTINCT ");
         }
-        buff.append(on.getSQL());
-        Window.appendOrderBy(buff, orderByList);
+        on.getSQL(builder);
+        Window.appendOrderBy(builder, orderByList);
         if (groupConcatSeparator != null) {
-            buff.append(" SEPARATOR ").append(groupConcatSeparator.getSQL());
+            builder.append(" SEPARATOR ");
+            groupConcatSeparator.getSQL(builder);
         }
-        buff.append(')');
-        return appendTailConditions(buff).toString();
+        builder.append(')');
+        return appendTailConditions(builder);
     }
 
-    private String getSQLArrayAggregate() {
-        StringBuilder buff = new StringBuilder("ARRAY_AGG(");
+    private StringBuilder getSQLArrayAggregate(StringBuilder builder) {
+        builder.append("ARRAY_AGG(");
         if (distinct) {
-            buff.append("DISTINCT ");
+            builder.append("DISTINCT ");
         }
-        buff.append(on.getSQL());
-        Window.appendOrderBy(buff, orderByList);
-        buff.append(')');
-        return appendTailConditions(buff).toString();
+        on.getSQL(builder);
+        Window.appendOrderBy(builder, orderByList);
+        builder.append(')');
+        return appendTailConditions(builder);
     }
 
     @Override
-    public String getSQL() {
+    public StringBuilder getSQL(StringBuilder builder) {
         String text;
         switch (type) {
         case GROUP_CONCAT:
-            return getSQLGroupConcat();
+            return getSQLGroupConcat(builder);
         case COUNT_ALL:
-            return appendTailConditions(new StringBuilder().append("COUNT(*)")).toString();
+            return appendTailConditions(builder.append("COUNT(*)"));
         case COUNT:
             text = "COUNT";
             break;
@@ -811,7 +811,7 @@ public class Aggregate extends AbstractAggregate {
             text = "MEDIAN";
             break;
         case ARRAY_AGG:
-            return getSQLArrayAggregate();
+            return getSQLArrayAggregate(builder);
         case MODE:
             text = "MODE";
             break;
@@ -821,13 +821,15 @@ public class Aggregate extends AbstractAggregate {
         default:
             throw DbException.throwInternalError("type=" + type);
         }
-        StringBuilder builder = new StringBuilder().append(text);
+        builder.append(text);
         if (distinct) {
-            builder.append("(DISTINCT ").append(on.getSQL()).append(')');
+            builder.append("(DISTINCT ");
+            on.getSQL(builder).append(')');
         } else {
-            builder.append(StringUtils.enclose(on.getSQL()));
+            builder.append('(');
+            on.getUnenclosedSQL(builder).append(')');
         }
-        return appendTailConditions(builder).toString();
+        return appendTailConditions(builder);
     }
 
     private Index getMinMaxColumnIndex() {

h2/src/main/org/h2/expression/aggregate/DataAnalysisOperation.java

@@ -351,7 +351,8 @@ public abstract class DataAnalysisOperation extends Expression {
 
     protected StringBuilder appendTailConditions(StringBuilder builder) {
         if (over != null) {
-            builder.append(' ').append(over.getSQL());
+            builder.append(' ');
+            over.getSQL(builder);
         }
         return builder;
     }

h2/src/main/org/h2/expression/aggregate/JavaAggregate.java

@@ -17,7 +17,6 @@ import org.h2.expression.ExpressionVisitor;
 import org.h2.message.DbException;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
-import org.h2.util.StatementBuilder;
 import org.h2.value.DataType;
 import org.h2.value.Value;
 import org.h2.value.ValueArray;
@@ -68,15 +67,11 @@ public class JavaAggregate extends AbstractAggregate {
     }
 
     @Override
-    public String getSQL() {
-        StatementBuilder buff = new StatementBuilder();
-        buff.append(Parser.quoteIdentifier(userAggregate.getName())).append('(');
-        for (Expression e : args) {
-            buff.appendExceptFirst(", ");
-            buff.append(e.getSQL());
-        }
-        buff.append(')');
-        return appendTailConditions(buff.builder()).toString();
+    public StringBuilder getSQL(StringBuilder builder) {
+        Parser.quoteIdentifier(builder, userAggregate.getName()).append('(');
+        writeExpressions(builder, args);
+        builder.append(')');
+        return appendTailConditions(builder);
     }
 
     @Override

h2/src/main/org/h2/expression/aggregate/Window.java

@@ -15,7 +15,6 @@ import org.h2.message.DbException;
 import org.h2.result.SortOrder;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
-import org.h2.util.StringUtils;
 import org.h2.value.Value;
 import org.h2.value.ValueArray;
 
@@ -49,7 +48,7 @@ public final class Window {
                 if (i > 0) {
                     builder.append(", ");
                 }
-                builder.append(o.expression.getSQL());
+                o.expression.getSQL(builder);
                 SortOrder.typeToString(builder, o.sortType);
             }
         }
@@ -204,23 +203,22 @@ public final class Window {
     }
 
     /**
-     * Returns SQL representation.
+     * Appends SQL representation to the specified builder.
      *
-     * @return SQL representation.
-     * @see Expression#getSQL()
+     * @param builder
+     *            string builder
+     * @return the specified string builder
+     * @see Expression#getSQL(StringBuilder)
      */
-    public String getSQL() {
-        if (partitionBy == null && orderBy == null && frame == null) {
-            return "OVER ()";
-        }
-        StringBuilder builder = new StringBuilder().append("OVER (");
+    public StringBuilder getSQL(StringBuilder builder) {
+        builder.append("OVER (");
         if (partitionBy != null) {
             builder.append("PARTITION BY ");
             for (int i = 0; i < partitionBy.size(); i++) {
                 if (i > 0) {
                     builder.append(", ");
                 }
-                builder.append(StringUtils.unEnclose(partitionBy.get(i).getSQL()));
+                partitionBy.get(i).getUnenclosedSQL(builder);
             }
         }
         appendOrderBy(builder, orderBy);
@@ -228,9 +226,9 @@ public final class Window {
             if (builder.charAt(builder.length() - 1) != '(') {
                 builder.append(' ');
             }
-            builder.append(frame.getSQL());
+            frame.getSQL(builder);
         }
-        return builder.append(')').toString();
+        return builder.append(')');
     }
 
     /**
@@ -257,7 +255,7 @@ public final class Window {
 
     @Override
     public String toString() {
-        return getSQL();
+        return getSQL(new StringBuilder()).toString();
     }
 
 }

h2/src/main/org/h2/expression/aggregate/WindowFrame.java

@@ -584,23 +584,27 @@ public final class WindowFrame {
     }
 
     /**
-     * Returns SQL representation.
+     * Append SQL representation to the specified builder.
      *
-     * @return SQL representation.
-     * @see org.h2.expression.Expression#getSQL()
+     * @param builder
+     *            string builder
+     * @return the specified string builder
+     * @see org.h2.expression.Expression#getSQL(StringBuilder)
      */
-    public String getSQL() {
-        StringBuilder builder = new StringBuilder();
+    public StringBuilder getSQL(StringBuilder builder) {
         builder.append(units.getSQL());
         if (following == null) {
-            builder.append(' ').append(starting.getSQL(false));
+            builder.append(' ');
+            starting.getSQL(builder, false);
         } else {
-            builder.append(" BETWEEN ").append(starting.getSQL(false)).append(" AND ").append(following.getSQL(true));
+            builder.append(" BETWEEN ");
+            starting.getSQL(builder, false).append(" AND ");
+            following.getSQL(builder, true);
         }
         if (exclusion != WindowFrameExclusion.EXCLUDE_NO_OTHERS) {
             builder.append(' ').append(exclusion.getSQL());
         }
-        return builder.toString();
+        return builder;
     }
 
 }

h2/src/main/org/h2/expression/aggregate/WindowFrameBound.java

@@ -52,19 +52,21 @@ public class WindowFrameBound {
     }
 
     /**
-     * Returns SQL representation.
+     * Appends SQL representation to the specified builder.
      *
+     * @param builder
+     *            string builder
      * @param following
      *            if false return SQL for starting clause, if true return SQL
      *            for following clause
-     * @return SQL representation.
-     * @see Expression#getSQL()
+     * @return the specified string builder
+     * @see Expression#getSQL(StringBuilder)
      */
-    public String getSQL(boolean following) {
+    public StringBuilder getSQL(StringBuilder builder, boolean following) {
         if (type == WindowFrameBoundType.PRECEDING || type == WindowFrameBoundType.FOLLOWING) {
-            return value.getSQL() + ' ' + type.getSQL();
+            value.getSQL(builder).append(' ');
         }
-        return type.getSQL();
+        return builder.append(type.getSQL());
     }
 
 }

h2/src/main/org/h2/expression/aggregate/WindowFunction.java

@@ -515,16 +515,11 @@ public class WindowFunction extends DataAnalysisOperation {
     }
 
     @Override
-    public String getSQL() {
+    public StringBuilder getSQL(StringBuilder builder) {
         String name = type.getSQL();
-        StringBuilder builder = new StringBuilder().append(name).append('(');
+        builder.append(name).append('(');
         if (args != null) {
-            for (int i = 0, numArgs = args.length; i < numArgs; i++) {
-                if (i > 0) {
-                    builder.append(", ");
-                }
-                builder.append(args[i].getSQL());
-            }
+            writeExpressions(builder, args);
         }
         builder.append(')');
         if (fromLast && type == WindowFunctionType.NTH_VALUE) {
@@ -542,7 +537,7 @@ public class WindowFunction extends DataAnalysisOperation {
             default:
             }
         }
-        return appendTailConditions(builder).toString();
+        return appendTailConditions(builder);
     }
 
     @Override

h2/src/main/org/h2/fulltext/FullText.java

@@ -514,7 +514,10 @@ public class FullText {
             if (data instanceof UUID) {
                 return "'" + data.toString() + "'";
             }
-            return "'" + StringUtils.convertBytesToHex((byte[]) data) + "'";
+            byte[] bytes = (byte[]) data;
+            StringBuilder builder = new StringBuilder(bytes.length * 2 + 2).append('\'');
+            StringUtils.convertBytesToHex(builder, bytes).append('\'');
+            return builder.toString();
         case Types.CLOB:
         case Types.JAVA_OBJECT:
         case Types.OTHER:
@@ -769,13 +772,13 @@ public class FullText {
                 if(!multiThread) {
                     buff.append(", ROLLBACK");
                 }
-                buff.append(" ON ").
-                        append(StringUtils.quoteIdentifier(schema)).
-                        append('.').
-                        append(StringUtils.quoteIdentifier(table)).
+                buff.append(" ON ");
+                StringUtils.quoteIdentifier(buff, schema).
+                        append('.');
+                StringUtils.quoteIdentifier(buff, table).
                         append(" FOR EACH ROW CALL \"").
                         append(FullText.FullTextTrigger.class.getName()).
-                        append('\"');
+                        append('"');
                 stat.execute(buff.toString());
             }
         }
@@ -1142,7 +1145,7 @@ public class FullText {
             StatementBuilder buff = new StatementBuilder();
             for (int columnIndex : index.keys) {
                 buff.appendExceptFirst(" AND ");
-                buff.append(StringUtils.quoteIdentifier(index.columns[columnIndex]));
+                StringUtils.quoteIdentifier(buff.builder(), index.columns[columnIndex]);
                 Object o = row[columnIndex];
                 if (o == null) {
                     buff.append(" IS NULL");

h2/src/main/org/h2/fulltext/FullTextLucene.java

@@ -281,19 +281,19 @@ public class FullTextLucene extends FullText {
                 StringUtils.quoteIdentifier(TRIGGER_PREFIX + table);
         stat.execute("DROP TRIGGER IF EXISTS " + trigger);
         if (create) {
-            StringBuilder buff = new StringBuilder(
+            StringBuilder builder = new StringBuilder(
                     "CREATE TRIGGER IF NOT EXISTS ");
             // the trigger is also called on rollback because transaction
             // rollback will not undo the changes in the Lucene index
-            buff.append(trigger).
-                append(" AFTER INSERT, UPDATE, DELETE, ROLLBACK ON ").
-                append(StringUtils.quoteIdentifier(schema)).
-                append('.').
-                append(StringUtils.quoteIdentifier(table)).
+            builder.append(trigger).
+                append(" AFTER INSERT, UPDATE, DELETE, ROLLBACK ON ");
+            StringUtils.quoteIdentifier(builder, schema).
+                append('.');
+            StringUtils.quoteIdentifier(builder, table).
                 append(" FOR EACH ROW CALL \"").
                 append(FullTextLucene.FullTextTrigger.class.getName()).
                 append('\"');
-            stat.execute(buff.toString());
+            stat.execute(builder.toString());
         }
     }
 
@@ -679,22 +679,25 @@ public class FullTextLucene extends FullText {
         }
 
         private String getQuery(Object[] row) throws SQLException {
-            StatementBuilder buff = new StatementBuilder();
+            StringBuilder builder = new StringBuilder();
             if (schema != null) {
-                buff.append(StringUtils.quoteIdentifier(schema)).append('.');
+                StringUtils.quoteIdentifier(builder, schema).append('.');
             }
-            buff.append(StringUtils.quoteIdentifier(table)).append(" WHERE ");
-            for (int columnIndex : keys) {
-                buff.appendExceptFirst(" AND ");
-                buff.append(StringUtils.quoteIdentifier(columns[columnIndex]));
+            StringUtils.quoteIdentifier(builder, table).append(" WHERE ");
+            for (int i = 0, length = keys.length; i < length; i++) {
+                if (i > 0) {
+                    builder.append(" AND ");
+                }
+                int columnIndex = keys[i];
+                StringUtils.quoteIdentifier(builder, columns[columnIndex]);
                 Object o = row[columnIndex];
                 if (o == null) {
-                    buff.append(" IS NULL");
+                    builder.append(" IS NULL");
                 } else {
-                    buff.append('=').append(FullText.quoteSQL(o, columnTypes[columnIndex]));
+                    builder.append('=').append(FullText.quoteSQL(o, columnTypes[columnIndex]));
                 }
             }
-            return buff.toString();
+            return builder.toString();
         }
     }
 

h2/src/main/org/h2/index/BaseIndex.java

@@ -410,7 +410,8 @@ public abstract class BaseIndex extends SchemaObjectBase implements Index {
         buff.append(quotedName);
         buff.append(" ON ").append(targetTable.getSQL());
         if (comment != null) {
-            buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
+            buff.append(" COMMENT ");
+            StringUtils.quoteStringSQL(buff, comment);
         }
         buff.append('(').append(getColumnListSQL()).append(')');
         return buff.toString();

h2/src/main/org/h2/index/IndexCondition.java

@@ -177,50 +177,47 @@ public class IndexCondition {
         if (compareType == Comparison.FALSE) {
             return "FALSE";
         }
-        StatementBuilder buff = new StatementBuilder();
-        buff.append(column.getSQL());
+        StringBuilder builder = new StringBuilder();
+        builder.append(column.getSQL());
         switch (compareType) {
         case Comparison.EQUAL:
-            buff.append(" = ");
+            builder.append(" = ");
             break;
         case Comparison.EQUAL_NULL_SAFE:
-            buff.append(" IS ");
+            builder.append(" IS ");
             break;
         case Comparison.BIGGER_EQUAL:
-            buff.append(" >= ");
+            builder.append(" >= ");
             break;
         case Comparison.BIGGER:
-            buff.append(" > ");
+            builder.append(" > ");
             break;
         case Comparison.SMALLER_EQUAL:
-            buff.append(" <= ");
+            builder.append(" <= ");
             break;
         case Comparison.SMALLER:
-            buff.append(" < ");
+            builder.append(" < ");
             break;
         case Comparison.IN_LIST:
-            buff.append(" IN(");
-            for (Expression e : expressionList) {
-                buff.appendExceptFirst(", ");
-                buff.append(e.getSQL());
-            }
-            buff.append(')');
+            builder.append(" IN(");
+            Expression.writeExpressions(builder, expressionList);
+            builder.append(')');
             break;
         case Comparison.IN_QUERY:
-            buff.append(" IN(");
-            buff.append(expressionQuery.getPlanSQL());
-            buff.append(')');
+            builder.append(" IN(");
+            builder.append(expressionQuery.getPlanSQL());
+            builder.append(')');
             break;
         case Comparison.SPATIAL_INTERSECTS:
-            buff.append(" && ");
+            builder.append(" && ");
             break;
         default:
             DbException.throwInternalError("type=" + compareType);
         }
         if (expression != null) {
-            buff.append(expression.getSQL());
+            expression.getSQL(builder);
         }
-        return buff.toString();
+        return builder.toString();
     }
 
     /**

h2/src/main/org/h2/jdbc/JdbcDatabaseMetaData.java

@@ -1624,9 +1624,10 @@ public class JdbcDatabaseMetaData extends TraceObject implements
                     int spaceIndex = f.indexOf(' ');
                     if (spaceIndex >= 0) {
                         // remove 'Function' from 'INSERT Function'
-                        f = StringUtils.trimSubstring(f, 0, spaceIndex);
+                        StringUtils.trimSubstring(buff.builder(), f, 0, spaceIndex);
+                    } else {
+                        buff.append(f);
                     }
-                    buff.append(f);
                 }
             }
             rs.close();
@@ -3092,14 +3093,14 @@ public class JdbcDatabaseMetaData extends TraceObject implements
     }
 
     private static String getSchemaPattern(String pattern) {
-        return pattern == null ? "%" : pattern.length() == 0 ?
+        return pattern == null ? "%" : pattern.isEmpty() ?
                 Constants.SCHEMA_MAIN : pattern;
     }
 
     private static String getCatalogPattern(String catalogPattern) {
         // Workaround for OpenOffice: getColumns is called with "" as the
         // catalog
-        return catalogPattern == null || catalogPattern.length() == 0 ?
+        return catalogPattern == null || catalogPattern.isEmpty() ?
                 "%" : catalogPattern;
     }
 

h2/src/main/org/h2/jdbcx/JdbcXid.java

@@ -44,8 +44,15 @@ public class JdbcXid extends TraceObject implements Xid {
      * INTERNAL
      */
     public static String toString(Xid xid) {
-        return PREFIX + '_' + xid.getFormatId() + '_' + StringUtils.convertBytesToHex(xid.getBranchQualifier()) + '_'
-                + StringUtils.convertBytesToHex(xid.getGlobalTransactionId());
+        StringBuilder builder = new StringBuilder()
+                .append(PREFIX)
+                .append('_')
+                .append(xid.getFormatId())
+                .append('_');
+        StringUtils.convertBytesToHex(builder, xid.getBranchQualifier())
+                .append('_');
+        StringUtils.convertBytesToHex(builder, xid.getGlobalTransactionId());
+        return builder.toString();
     }
 
     /**

h2/src/main/org/h2/message/Trace.java

@@ -301,8 +301,8 @@ public class Trace {
             buff.append(' ');
         }
         buff.append("*/");
-        StringUtils.javaEncode(sql, buff);
-        StringUtils.javaEncode(params, buff);
+        StringUtils.javaEncode(sql, buff, false);
+        StringUtils.javaEncode(params, buff, false);
         buff.append(';');
         sql = buff.toString();
         traceWriter.write(TraceSystem.INFO, module, sql, null);

h2/src/main/org/h2/message/TraceObject.java

@@ -312,8 +312,9 @@ public class TraceObject {
         if (x == null) {
             return "null";
         }
-        return "org.h2.util.StringUtils.convertHexToBytes(\"" +
-                StringUtils.convertBytesToHex(x) + "\")";
+        StringBuilder builder = new StringBuilder(x.length * 2 + 45)
+                .append("org.h2.util.StringUtils.convertHexToBytes(\"");
+        return StringUtils.convertBytesToHex(builder, x).append("\")").toString();
     }
 
     /**

h2/src/main/org/h2/res/_messages_de.prop

@@ -35,7 +35,7 @@
 57014=Befehl wurde abgebrochen oder das Session-Timeout ist abgelaufen
 90000=Funktion {0} muss Zeilen zurückgeben
 90001=Methode nicht zulässig für eine Abfrage. Erlaubt sind execute oder executeQuery, nicht jedoch executeUpdate
-90002=Methode nur zulässig for eine Abfrage. Erlaubt sind execute oder executeUpdate, nicht jedoch executeQuery
+90002=Methode nur zulässig für eine Abfrage. Erlaubt sind execute oder executeUpdate, nicht jedoch executeQuery
 90003=Hexadezimal Zahl mit einer ungeraden Anzahl Zeichen: {0}
 90004=Hexadezimal Zahl enthält unerlaubtes Zeichen: {0}
 90006=Die Sequenz {0} hat keine freien Nummern mehr

h2/src/main/org/h2/result/SortOrder.java

@@ -12,8 +12,6 @@ import org.h2.expression.Expression;
 import org.h2.expression.ExpressionColumn;
 import org.h2.table.Column;
 import org.h2.table.TableFilter;
-import org.h2.util.StatementBuilder;
-import org.h2.util.StringUtils;
 import org.h2.util.Utils;
 import org.h2.value.Value;
 import org.h2.value.ValueNull;
@@ -118,18 +116,21 @@ public class SortOrder implements Comparator<Value[]> {
      * @return the SQL snippet
      */
     public String getSQL(Expression[] list, int visible) {
-        StatementBuilder buff = new StatementBuilder();
+        StringBuilder builder = new StringBuilder();
         int i = 0;
         for (int idx : queryColumnIndexes) {
-            buff.appendExceptFirst(", ");
+            if (i > 0) {
+                builder.append(", ");
+            }
             if (idx < visible) {
-                buff.append(idx + 1);
+                builder.append(idx + 1);
             } else {
-                buff.append('=').append(StringUtils.unEnclose(list[idx].getSQL()));
+                builder.append('=');
+                list[idx].getUnenclosedSQL(builder);
             }
-            typeToString(buff.builder(), sortTypes[i++]);
+            typeToString(builder, sortTypes[i++]);
         }
-        return buff.toString();
+        return builder.toString();
     }
 
     /**

h2/src/main/org/h2/result/UpdatableRow.java

@@ -161,7 +161,7 @@ public class UpdatableRow {
         for (int i = 0; i < columnCount; i++) {
             buff.appendExceptFirst(",");
             String col = result.getColumnName(i);
-            buff.append(StringUtils.quoteIdentifier(col));
+            StringUtils.quoteIdentifier(buff.builder(), col);
             if (set) {
                 buff.append("=? ");
             }
@@ -173,7 +173,7 @@ public class UpdatableRow {
         buff.resetCount();
         for (String k : key) {
             buff.appendExceptFirst(" AND ");
-            buff.append(StringUtils.quoteIdentifier(k)).append("=?");
+            StringUtils.quoteIdentifier(buff.builder(), k).append("=?");
         }
     }
 
@@ -204,11 +204,11 @@ public class UpdatableRow {
 //        return rs.getInt(1) == 0;
 //    }
 
-    private void appendTableName(StatementBuilder buff) {
+    private void appendTableName(StringBuilder builder) {
         if (schemaName != null && schemaName.length() > 0) {
-            buff.append(StringUtils.quoteIdentifier(schemaName)).append('.');
+            StringUtils.quoteIdentifier(builder, schemaName).append('.');
         }
-        buff.append(StringUtils.quoteIdentifier(tableName));
+        StringUtils.quoteIdentifier(builder, tableName);
     }
 
     /**
@@ -221,7 +221,7 @@ public class UpdatableRow {
         StatementBuilder buff = new StatementBuilder("SELECT ");
         appendColumnList(buff, false);
         buff.append(" FROM ");
-        appendTableName(buff);
+        appendTableName(buff.builder());
         appendKeyCondition(buff);
         PreparedStatement prep = conn.prepareStatement(buff.toString());
         setKey(prep, 1, row);
@@ -245,7 +245,7 @@ public class UpdatableRow {
      */
     public void deleteRow(Value[] current) throws SQLException {
         StatementBuilder buff = new StatementBuilder("DELETE FROM ");
-        appendTableName(buff);
+        appendTableName(buff.builder());
         appendKeyCondition(buff);
         PreparedStatement prep = conn.prepareStatement(buff.toString());
         setKey(prep, 1, current);
@@ -265,7 +265,7 @@ public class UpdatableRow {
      */
     public void updateRow(Value[] current, Value[] updateRow) throws SQLException {
         StatementBuilder buff = new StatementBuilder("UPDATE ");
-        appendTableName(buff);
+        appendTableName(buff.builder());
         buff.append(" SET ");
         appendColumnList(buff, true);
         // TODO updatable result set: we could add all current values to the
@@ -297,7 +297,7 @@ public class UpdatableRow {
      */
     public void insertRow(Value[] row) throws SQLException {
         StatementBuilder buff = new StatementBuilder("INSERT INTO ");
-        appendTableName(buff);
+        appendTableName(buff.builder());
         buff.append('(');
         appendColumnList(buff, false);
         buff.append(")VALUES(");

h2/src/main/org/h2/schema/Constant.java

@@ -38,7 +38,8 @@ public class Constant extends SchemaObjectBase {
 
     @Override
     public String getCreateSQL() {
-        return "CREATE CONSTANT " + getSQL() + " VALUE " + value.getSQL();
+        StringBuilder builder = new StringBuilder().append("CREATE CONSTANT ").append(getSQL()).append(" VALUE ");
+        return value.getSQL(builder).toString();
     }
 
     @Override

h2/src/main/org/h2/schema/TriggerObject.java

@@ -345,9 +345,11 @@ public class TriggerObject extends SchemaObjectBase {
             buff.append(" QUEUE ").append(queueSize);
         }
         if (triggerClassName != null) {
-            buff.append(" CALL ").append(Parser.quoteIdentifier(triggerClassName));
+            buff.append(" CALL ");
+            Parser.quoteIdentifier(buff, triggerClassName);
         } else {
-            buff.append(" AS ").append(StringUtils.quoteStringSQL(triggerSource));
+            buff.append(" AS ");
+            StringUtils.quoteStringSQL(buff, triggerSource);
         }
         return buff.toString();
     }

h2/src/main/org/h2/server/pg/PgServerThread.java

@@ -180,7 +180,7 @@ public class PgServerThread implements Runnable {
                         " (" + (version >> 16) + "." + (version & 0xff) + ")");
                 while (true) {
                     String param = readString();
-                    if (param.length() == 0) {
+                    if (param.isEmpty()) {
                         break;
                     }
                     String value = readString();

h2/src/main/org/h2/server/web/PageParser.java

@@ -240,14 +240,15 @@ public class PageParser {
         if (s == null) {
             return null;
         }
+        int length = s.length();
         if (convertBreakAndSpace) {
-            if (s.length() == 0) {
+            if (length == 0) {
                 return " ";
             }
         }
-        StringBuilder buff = new StringBuilder(s.length());
+        StringBuilder buff = new StringBuilder(length);
         boolean convertSpace = true;
-        for (int i = 0; i < s.length(); i++) {
+        for (int i = 0; i < length; i++) {
             char c = s.charAt(i);
             if (c == ' ' || c == '\t') {
                 // convert tabs into spaces
@@ -312,11 +313,12 @@ public class PageParser {
         if (s == null) {
             return null;
         }
-        if (s.length() == 0) {
+        int length = s.length();
+        if (length == 0) {
             return "";
         }
-        StringBuilder buff = new StringBuilder(s.length());
-        for (int i = 0; i < s.length(); i++) {
+        StringBuilder buff = new StringBuilder(length);
+        for (int i = 0; i < length; i++) {
             char c = s.charAt(i);
             switch (c) {
             case '"':

h2/src/main/org/h2/server/web/WebSession.java

@@ -167,7 +167,7 @@ class WebSession {
             return;
         }
         sql = sql.trim();
-        if (sql.length() == 0) {
+        if (sql.isEmpty()) {
             return;
         }
         if (commandHistory.size() > MAX_HISTORY) {

h2/src/main/org/h2/store/fs/FilePathZip.java

@@ -51,7 +51,7 @@ public class FilePathZip extends FilePath {
     public boolean exists() {
         try {
             String entryName = getEntryName();
-            if (entryName.length() == 0) {
+            if (entryName.isEmpty()) {
                 return true;
             }
             try (ZipFile file = openZipFile()) {
@@ -88,7 +88,7 @@ public class FilePathZip extends FilePath {
     public boolean isDirectory() {
         try {
             String entryName = getEntryName();
-            if (entryName.length() == 0) {
+            if (entryName.isEmpty()) {
                 return true;
             }
             try (ZipFile file = openZipFile()) {

h2/src/main/org/h2/table/Column.java

@@ -174,7 +174,7 @@ public class Column {
                         getCreateSQL();
                 throw DbException.get(
                         ErrorCode.DATA_CONVERSION_ERROR_1, e,
-                        v.getSQL() + " (" + target + ")");
+                        v.getTraceSQL() + " (" + target + ")");
             }
             throw e;
         }
@@ -496,7 +496,7 @@ public class Column {
     private String getCreateSQL(boolean includeName) {
         StringBuilder buff = new StringBuilder();
         if (includeName && name != null) {
-            buff.append(Parser.quoteIdentifier(name)).append(' ');
+            Parser.quoteIdentifier(buff, name).append(' ');
         }
         if (originalSQL != null) {
             buff.append(originalSQL);
@@ -546,20 +546,17 @@ public class Column {
         }
 
         if (defaultExpression != null) {
-            String sql = defaultExpression.getSQL();
-            if (sql != null) {
-                if (isComputed) {
-                    buff.append(" AS ").append(sql);
-                } else if (defaultExpression != null) {
-                    buff.append(" DEFAULT ").append(sql);
-                }
+            if (isComputed) {
+                buff.append(" AS ");
+                defaultExpression.getSQL(buff);
+            } else if (defaultExpression != null) {
+                buff.append(" DEFAULT ");
+                defaultExpression.getSQL(buff);
             }
         }
         if (onUpdateExpression != null) {
-            String sql = onUpdateExpression.getSQL();
-            if (sql != null) {
-                buff.append(" ON UPDATE ").append(sql);
-            }
+            buff.append(" ON UPDATE ");
+            onUpdateExpression.getSQL(buff);
         }
         if (!nullable) {
             buff.append(" NOT NULL");
@@ -576,7 +573,8 @@ public class Column {
             buff.append(" SELECTIVITY ").append(selectivity);
         }
         if (comment != null) {
-            buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
+            buff.append(" COMMENT ");
+            StringUtils.quoteStringSQL(buff, comment);
         }
         if (checkConstraint != null) {
             buff.append(" CHECK ").append(checkConstraintSQL);

h2/src/main/org/h2/table/LinkSchema.java

@@ -49,8 +49,8 @@ public class LinkSchema {
         try {
             c2 = JdbcUtils.getConnection(driver, url, user, password);
             stat = conn.createStatement();
-            stat.execute("CREATE SCHEMA IF NOT EXISTS " +
-                        StringUtils.quoteIdentifier(targetSchema));
+            stat.execute(StringUtils.quoteIdentifier(new StringBuilder("CREATE SCHEMA IF NOT EXISTS "), targetSchema)
+                    .toString());
             //Workaround for PostgreSQL to avoid index names
             if (url.startsWith("jdbc:postgresql:")) {
                 rs = c2.getMetaData().getTables(null, sourceSchema, null,
@@ -61,29 +61,23 @@ public class LinkSchema {
             while (rs.next()) {
                 String table = rs.getString("TABLE_NAME");
                 StringBuilder buff = new StringBuilder();
-                buff.append("DROP TABLE IF EXISTS ").
-                    append(StringUtils.quoteIdentifier(targetSchema)).
-                    append('.').
-                    append(StringUtils.quoteIdentifier(table));
+                buff.append("DROP TABLE IF EXISTS ");
+                StringUtils.quoteIdentifier(buff, targetSchema).
+                    append('.');
+                StringUtils.quoteIdentifier(buff, table);
                 stat.execute(buff.toString());
-                buff = new StringBuilder();
-                buff.append("CREATE LINKED TABLE ").
-                    append(StringUtils.quoteIdentifier(targetSchema)).
-                    append('.').
-                    append(StringUtils.quoteIdentifier(table)).
-                    append('(').
-                    append(StringUtils.quoteStringSQL(driver)).
-                    append(", ").
-                    append(StringUtils.quoteStringSQL(url)).
-                    append(", ").
-                    append(StringUtils.quoteStringSQL(user)).
-                    append(", ").
-                    append(StringUtils.quoteStringSQL(password)).
-                    append(", ").
-                    append(StringUtils.quoteStringSQL(sourceSchema)).
-                    append(", ").
-                    append(StringUtils.quoteStringSQL(table)).
-                    append(')');
+                buff.setLength(0);
+                buff.append("CREATE LINKED TABLE ");
+                StringUtils.quoteIdentifier(buff, targetSchema).
+                    append('.');
+                StringUtils.quoteIdentifier(buff, table).
+                    append('(');
+                StringUtils.quoteStringSQL(buff, driver).append(", ");
+                StringUtils.quoteStringSQL(buff, url).append(", ");
+                StringUtils.quoteStringSQL(buff, user).append(", ");
+                StringUtils.quoteStringSQL(buff, password).append(", ");
+                StringUtils.quoteStringSQL(buff, sourceSchema).append(", ");
+                StringUtils.quoteStringSQL(buff, table).append(')');
                 stat.execute(buff.toString());
                 result.addRow(table);
             }

h2/src/main/org/h2/table/MetaTable.java

@@ -1896,11 +1896,12 @@ public class MetaTable extends Table {
         case SESSION_STATE: {
             for (String name : session.getVariableNames()) {
                 Value v = session.getVariable(name);
+                StringBuilder builder = new StringBuilder().append("SET @").append(name).append(' ');
+                v.getSQL(builder);
                 add(rows,
                         // KEY
                         "@" + name,
-                        // SQL
-                        "SET @" + name + " " + v.getSQL()
+                        builder.toString()
                 );
             }
             for (Table table : session.getLocalTempTables()) {
@@ -1917,7 +1918,7 @@ public class MetaTable extends Table {
                         "SET SCHEMA_SEARCH_PATH ");
                 for (String p : path) {
                     buff.appendExceptFirst(", ");
-                    buff.append(StringUtils.quoteIdentifier(p));
+                    StringUtils.quoteIdentifier(buff.builder(), p);
                 }
                 add(rows,
                         // KEY
@@ -1932,7 +1933,7 @@ public class MetaTable extends Table {
                         // KEY
                         "SCHEMA",
                         // SQL
-                        "SET SCHEMA " + StringUtils.quoteIdentifier(schema)
+                        StringUtils.quoteIdentifier(new StringBuilder("SET SCHEMA "), schema).toString()
                 );
             }
             break;

h2/src/main/org/h2/table/RangeTable.java

@@ -72,11 +72,15 @@ public class RangeTable extends Table {
 
     @Override
     public String getSQL() {
-        String sql = NAME + "(" + min.getSQL() + ", " + max.getSQL();
+        StringBuilder builder = new StringBuilder();
+        builder.append(NAME).append('(');
+        min.getSQL(builder).append(", ");
+        max.getSQL(builder);
         if (step != null) {
-            sql += ", " + step.getSQL();
+            builder.append(", ");
+            step.getSQL(builder);
         }
-        return sql + ")";
+        return builder.append(')').toString();
     }
 
     @Override

h2/src/main/org/h2/table/TableBase.java

@@ -108,7 +108,8 @@ public abstract class TableBase extends Table {
         }
         buff.append(getSQL());
         if (comment != null) {
-            buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
+            buff.append(" COMMENT ");
+            StringUtils.quoteStringSQL(buff.builder(), comment);
         }
         buff.append("(\n    ");
         for (Column column : columns) {
@@ -124,7 +125,7 @@ public abstract class TableBase extends Table {
             }
             if (d == null || !tableEngine.endsWith(d)) {
                 buff.append("\nENGINE ");
-                buff.append(StringUtils.quoteIdentifier(tableEngine));
+                StringUtils.quoteIdentifier(buff.builder(), tableEngine);
             }
         }
         if (!tableEngineParams.isEmpty()) {
@@ -132,7 +133,7 @@ public abstract class TableBase extends Table {
             buff.resetCount();
             for (String parameter : tableEngineParams) {
                 buff.appendExceptFirst(", ");
-                buff.append(StringUtils.quoteIdentifier(parameter));
+                StringUtils.quoteIdentifier(buff.builder(), parameter);
             }
         }
         if (!isPersistIndexes() && !isPersistData()) {

h2/src/main/org/h2/table/TableFilter.java

@@ -747,75 +747,77 @@ public class TableFilter implements ColumnResolver {
     }
 
     /**
-     * Get the query execution plan text to use for this table filter.
+     * Get the query execution plan text to use for this table filter and append
+     * it to the specified builder.
      *
+     * @param builder string builder to append to
      * @param isJoin if this is a joined table
-     * @return the SQL statement snippet
+     * @return the specified builder
      */
-    public String getPlanSQL(boolean isJoin) {
-        StringBuilder buff = new StringBuilder();
+    public StringBuilder getPlanSQL(StringBuilder builder, boolean isJoin) {
         if (isJoin) {
             if (joinOuter) {
-                buff.append("LEFT OUTER JOIN ");
+                builder.append("LEFT OUTER JOIN ");
             } else {
-                buff.append("INNER JOIN ");
+                builder.append("INNER JOIN ");
             }
         }
         if (nestedJoin != null) {
             StringBuilder buffNested = new StringBuilder();
             TableFilter n = nestedJoin;
             do {
-                buffNested.append(n.getPlanSQL(n != nestedJoin));
-                buffNested.append('\n');
+                n.getPlanSQL(buffNested, n != nestedJoin).append('\n');
                 n = n.getJoin();
             } while (n != null);
             String nested = buffNested.toString();
             boolean enclose = !nested.startsWith("(");
             if (enclose) {
-                buff.append("(\n");
+                builder.append("(\n");
             }
-            buff.append(StringUtils.indent(nested, 4, false));
+            StringUtils.indent(builder, nested, 4, false);
             if (enclose) {
-                buff.append(')');
+                builder.append(')');
             }
             if (isJoin) {
-                buff.append(" ON ");
+                builder.append(" ON ");
                 if (joinCondition == null) {
                     // need to have a ON expression,
                     // otherwise the nesting is unclear
-                    buff.append("1=1");
+                    builder.append("1=1");
                 } else {
-                    buff.append(StringUtils.unEnclose(joinCondition.getSQL()));
+                    joinCondition.getUnenclosedSQL(builder);
                 }
             }
-            return buff.toString();
+            return builder;
         }
         if (table.isView() && ((TableView) table).isRecursive()) {
-            buff.append(table.getSchema().getSQL()).append('.').append(Parser.quoteIdentifier(table.getName()));
+            builder.append(table.getSchema().getSQL()).append('.');
+            Parser.quoteIdentifier(builder, table.getName());
         } else {
-            buff.append(table.getSQL());
+            builder.append(table.getSQL());
         }
         if (table.isView() && ((TableView) table).isInvalid()) {
             throw DbException.get(ErrorCode.VIEW_IS_INVALID_2, table.getName(), "not compiled");
         }
         if (alias != null) {
-            buff.append(' ').append(Parser.quoteIdentifier(alias));
+            builder.append(' ');
+            Parser.quoteIdentifier(builder, alias);
         }
         if (indexHints != null) {
-            buff.append(" USE INDEX (");
+            builder.append(" USE INDEX (");
             boolean first = true;
             for (String index : indexHints.getAllowedIndexes()) {
                 if (!first) {
-                    buff.append(", ");
+                    builder.append(", ");
                 } else {
                     first = false;
                 }
-                buff.append(Parser.quoteIdentifier(index));
+                Parser.quoteIdentifier(builder, index);
             }
-            buff.append(")");
+            builder.append(")");
         }
         if (index != null) {
-            buff.append('\n');
+            builder.append('\n');
             StatementBuilder planBuff = new StatementBuilder();
             if (joinBatch != null) {
                 IndexLookupBatch lookupBatch = joinBatch.getLookupBatch(joinFilterId);
@@ -842,28 +844,28 @@ public class TableFilter implements ColumnResolver {
             if (plan.indexOf('\n') >= 0) {
                 plan += "\n";
             }
-            buff.append(StringUtils.indent("/* " + plan + " */", 4, false));
+            StringUtils.indent(builder, "/* " + plan + " */", 4, false);
         }
         if (isJoin) {
-            buff.append("\n    ON ");
+            builder.append("\n    ON ");
             if (joinCondition == null) {
                 // need to have a ON expression, otherwise the nesting is
                 // unclear
-                buff.append("1=1");
+                builder.append("1=1");
             } else {
-                buff.append(StringUtils.unEnclose(joinCondition.getSQL()));
+                joinCondition.getUnenclosedSQL(builder);
             }
         }
         if (filterCondition != null) {
-            buff.append('\n');
+            builder.append('\n');
             String condition = StringUtils.unEnclose(filterCondition.getSQL());
             condition = "/* WHERE " + StringUtils.quoteRemarkSQL(condition) + "\n*/";
-            buff.append(StringUtils.indent(condition, 4, false));
+            StringUtils.indent(builder, condition, 4, false);
         }
         if (scanCount > 0) {
-            buff.append("\n    /* scanCount: ").append(scanCount).append(" */");
+            builder.append("\n    /* scanCount: ").append(scanCount).append(" */");
         }
-        return buff.toString();
+        return builder;
     }
 
     /**

h2/src/main/org/h2/table/TableLink.java

@@ -372,19 +372,15 @@ public class TableLink extends Table {
         }
         buff.append("LINKED TABLE ").append(getSQL());
         if (comment != null) {
-            buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
+            buff.append(" COMMENT ");
+            StringUtils.quoteStringSQL(buff, comment);
         }
-        buff.append('(').
-            append(StringUtils.quoteStringSQL(driver)).
-            append(", ").
-            append(StringUtils.quoteStringSQL(url)).
-            append(", ").
-            append(StringUtils.quoteStringSQL(user)).
-            append(", ").
-            append(StringUtils.quoteStringSQL(password)).
-            append(", ").
-            append(StringUtils.quoteStringSQL(originalTable)).
-            append(')');
+        buff.append('(');
+        StringUtils.quoteStringSQL(buff, driver).append(", ");
+        StringUtils.quoteStringSQL(buff, url).append(", ");
+        StringUtils.quoteStringSQL(buff, user).append(", ");
+        StringUtils.quoteStringSQL(buff, password).append(", ");
+        StringUtils.quoteStringSQL(buff, originalTable).append(')');
         if (emitUpdates) {
             buff.append(" EMIT UPDATES");
         }
@@ -510,7 +506,8 @@ public class TableLink extends Table {
                             int i = 1;
                             for (Value v : params) {
                                 buff.appendExceptFirst(", ");
-                                buff.append(i++).append(": ").append(v.getSQL());
+                                buff.append(i++).append(": ");
+                                v.getSQL(buff.builder());
                             }
                             buff.append('}');
                         }

h2/src/main/org/h2/table/TableView.java

@@ -348,7 +348,8 @@ public class TableView extends Table {
         }
         buff.append(quotedName);
         if (comment != null) {
-            buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
+            buff.append(" COMMENT ");
+            StringUtils.quoteStringSQL(buff.builder(), comment);
         }
         if (columns != null && columns.length > 0) {
             buff.append('(');
@@ -467,7 +468,8 @@ public class TableView extends Table {
     @Override
     public String getSQL() {
         if (isTemporary() && querySQL != null) {
-            return "(\n" + StringUtils.indent(querySQL) + ")";
+            StringBuilder builder = new StringBuilder(querySQL.length() + 16).append("(\n");
+            return StringUtils.indent(builder, querySQL, 4, true).append(')').toString();
         }
         return super.getSQL();
     }

h2/src/main/org/h2/tools/Backup.java

@@ -108,7 +108,7 @@ public class Backup extends Tool {
     private void process(String zipFileName, String directory, String db,
             boolean quiet) throws SQLException {
         List<String> list;
-        boolean allFiles = db != null && db.length() == 0;
+        boolean allFiles = db != null && db.isEmpty();
         if (allFiles) {
             list = FileUtils.newDirectoryStream(directory);
         } else {

h2/src/main/org/h2/tools/Csv.java

@@ -228,7 +228,7 @@ public class Csv implements SimpleRowSource {
         for (int i = 0; i < columnNames.length; i++) {
             StringBuilder buff = new StringBuilder();
             String n = columnNames[i];
-            if (n == null || n.length() == 0) {
+            if (n == null || n.isEmpty()) {
                 buff.append('C').append(i + 1);
             } else {
                 buff.append(n);
@@ -350,7 +350,7 @@ public class Csv implements SimpleRowSource {
                     list.add(v);
                 }
             } else {
-                if (v.length() == 0) {
+                if (v.isEmpty()) {
                     v = "COLUMN" + list.size();
                 } else if (!caseSensitiveColumnNames && isSimpleColumnName(v)) {
                     v = StringUtils.toUpperEnglish(v);
@@ -827,13 +827,13 @@ public class Csv implements SimpleRowSource {
         String charset = null;
         String[] keyValuePairs = StringUtils.arraySplit(options, ' ', false);
         for (String pair : keyValuePairs) {
-            if (pair.length() == 0) {
+            if (pair.isEmpty()) {
                 continue;
             }
             int index = pair.indexOf('=');
             String key = StringUtils.trim(pair.substring(0, index), true, true, " ");
             String value = pair.substring(index + 1);
-            char ch = value.length() == 0 ? 0 : value.charAt(0);
+            char ch = value.isEmpty() ? 0 : value.charAt(0);
             if (isParam(key, "escape", "esc", "escapeCharacter")) {
                 setEscapeCharacter(ch);
             } else if (isParam(key, "fieldDelimiter", "fieldDelim")) {

h2/src/main/org/h2/tools/MultiDimension.java

@@ -156,12 +156,13 @@ public class MultiDimension implements Comparator<long[]> {
     public String generatePreparedQuery(String table, String scalarColumn,
             String[] columns) {
         StringBuilder buff = new StringBuilder("SELECT D.* FROM ");
-        buff.append(StringUtils.quoteIdentifier(table)).
-            append(" D, TABLE(_FROM_ BIGINT=?, _TO_ BIGINT=?) WHERE ").
-            append(StringUtils.quoteIdentifier(scalarColumn)).
+        StringUtils.quoteIdentifier(buff, table).
+            append(" D, TABLE(_FROM_ BIGINT=?, _TO_ BIGINT=?) WHERE ");
+        StringUtils.quoteIdentifier(buff, scalarColumn).
             append(" BETWEEN _FROM_ AND _TO_");
         for (String col : columns) {
-            buff.append(" AND ").append(StringUtils.quoteIdentifier(col)).
+            buff.append(" AND ");
+            StringUtils.quoteIdentifier(buff, col).
                 append("+1 BETWEEN ?+1 AND ?+1");
         }
         return buff.toString();

h2/src/main/org/h2/tools/Recover.java

@@ -417,7 +417,7 @@ public class Recover extends Tool implements DataHandler {
         }
     }
 
-    private String getSQL(String column, Value v) {
+    private void getSQL(StringBuilder builder, String column, Value v) {
         if (v instanceof ValueLob) {
             ValueLob lob = (ValueLob) v;
             byte[] small = lob.getSmall();
@@ -428,7 +428,8 @@ public class Recover extends Tool implements DataHandler {
                     dumpLob(file, true);
                     file += ".comp";
                 }
-                return "READ_" + type + "('" + file + ".txt')";
+                builder.append("READ_").append(type).append("('").append(file).append(".txt')");
+                return;
             }
         } else if (v instanceof ValueLobDb) {
             ValueLobDb lob = (ValueLobDb) v;
@@ -437,25 +438,25 @@ public class Recover extends Tool implements DataHandler {
                 int type = lob.getType();
                 long id = lob.getLobId();
                 long precision = lob.getPrecision();
-                String m;
                 String columnType;
                 if (type == Value.BLOB) {
                     columnType = "BLOB";
-                    m = "READ_BLOB";
+                    builder.append("READ_BLOB");
                 } else {
                     columnType = "CLOB";
-                    m = "READ_CLOB";
+                    builder.append("READ_CLOB");
                 }
                 if (lobMaps) {
-                    m += "_MAP";
+                    builder.append("_MAP");
                 } else {
-                    m += "_DB";
+                    builder.append("_DB");
                 }
                 columnTypeMap.put(column, columnType);
-                return m + "(" + id + ", " + precision + ")";
+                builder.append('(').append(id).append(", ").append(precision).append(')');
+                return;
             }
         }
-        return v.getSQL();
+        v.getSQL(builder);
     }
 
     private void setDatabaseName(String name) {
@@ -666,9 +667,11 @@ public class Recover extends Tool implements DataHandler {
                     if (!init) {
                         setStorage(Integer.parseInt(tableId));
                         // init the column types
+                        StringBuilder builder = new StringBuilder();
                         for (valueId = 0; valueId < recordLength; valueId++) {
                             String columnName = storageName + "." + valueId;
-                            getSQL(columnName, values[valueId]);
+                            builder.setLength(0);
+                            getSQL(builder, columnName, values[valueId]);
                         }
                         createTemporaryTable(writer);
                         init = true;
@@ -681,7 +684,7 @@ public class Recover extends Tool implements DataHandler {
                             buff.append(", ");
                         }
                         String columnName = storageName + "." + valueId;
-                        buff.append(getSQL(columnName, values[valueId]));
+                        getSQL(buff, columnName, values[valueId]);
                     }
                     buff.append(");");
                     writer.println(buff.toString());
@@ -729,10 +732,11 @@ public class Recover extends Tool implements DataHandler {
             try {
                 for (int seq = 0;; seq++) {
                     int l = IOUtils.readFully(in, block, block.length);
-                    String x = StringUtils.convertBytesToHex(block, l);
                     if (l > 0) {
-                        writer.println("INSERT INTO INFORMATION_SCHEMA.LOB_BLOCKS " +
-                                "VALUES(" + lobId + ", " + seq + ", '" + x + "');");
+                        writer.print("INSERT INTO INFORMATION_SCHEMA.LOB_BLOCKS " +
+                                "VALUES(" + lobId + ", " + seq + ", '");
+                        writer.print(StringUtils.convertBytesToHex(block, l));
+                        writer.println("');");
                     }
                     if (l != len) {
                         break;
@@ -991,7 +995,7 @@ public class Recover extends Tool implements DataHandler {
                                     append(" VALUES(");
                             for (int i = 0; i < row.getColumnCount(); i++) {
                                 buff.appendExceptFirst(", ");
-                                buff.append(row.getValue(i).getSQL());
+                                row.getValue(i).getSQL(buff.builder());
                             }
                             buff.append(");");
                             writer.println(buff.toString());
@@ -1443,12 +1447,12 @@ public class Recover extends Tool implements DataHandler {
                             byte[] salt = MathUtils.secureRandomBytes(Constants.SALT_LEN);
                             byte[] passwordHash = SHA256.getHashWithSalt(
                                     userPasswordHash, salt);
-                            StringBuilder buff = new StringBuilder();
-                            buff.append("SALT '").
-                                append(StringUtils.convertBytesToHex(salt)).
-                                append("' HASH '").
-                                append(StringUtils.convertBytesToHex(passwordHash)).
-                                append('\'');
+                            StringBuilder buff = new StringBuilder()
+                                    .append("SALT '");
+                            StringUtils.convertBytesToHex(buff, salt)
+                                    .append("' HASH '");
+                            StringUtils.convertBytesToHex(buff, passwordHash)
+                                    .append('\'');
                             byte[] replacement = buff.toString().getBytes();
                             System.arraycopy(replacement, 0, s.getBytes(),
                                     saltIndex, replacement.length);
@@ -1497,7 +1501,7 @@ public class Recover extends Tool implements DataHandler {
                     sb.append(", ");
                 }
                 String columnName = storageName + "." + valueId;
-                sb.append(getSQL(columnName, v));
+                getSQL(sb, columnName, v);
             } catch (Exception e) {
                 writeDataError(writer, "exception " + e, s.getBytes());
             } catch (OutOfMemoryError e) {

h2/src/main/org/h2/tools/RunScript.java

@@ -205,7 +205,7 @@ public class RunScript extends Tool {
                 break;
             }
             String trim = sql.trim();
-            if (trim.length() == 0) {
+            if (trim.isEmpty()) {
                 continue;
             }
             if (trim.startsWith("@") && StringUtils.toUpperEnglish(trim).

h2/src/main/org/h2/tools/Shell.java

@@ -220,7 +220,7 @@ public class Shell extends Tool implements Runnable {
                     break;
                 }
                 String trimmed = line.trim();
-                if (trimmed.length() == 0) {
+                if (trimmed.isEmpty()) {
                     continue;
                 }
                 boolean end = trimmed.endsWith(";");
@@ -366,7 +366,7 @@ public class Shell extends Tool implements Runnable {
         println("[Enter]   Hide");
         print("Password  ");
         String password = readLine();
-        if (password.length() == 0) {
+        if (password.isEmpty()) {
             password = readPassword();
         }
         conn = JdbcUtils.getConnection(driver, url, user, password);
@@ -433,7 +433,7 @@ public class Shell extends Tool implements Runnable {
 
     private String readLine(String defaultValue) throws IOException {
         String s = readLine();
-        return s.length() == 0 ? defaultValue : s;
+        return s.isEmpty() ? defaultValue : s;
     }
 
     private String readLine() throws IOException {

h2/src/main/org/h2/util/ColumnNamer.java

@@ -6,7 +6,7 @@ package org.h2.util;
 
 import java.util.HashSet;
 import java.util.Set;
-import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 import org.h2.engine.Session;
 import org.h2.expression.Expression;
 
@@ -57,51 +57,23 @@ public class ColumnNamer {
      */
     public String getColumnName(Expression columnExp, int indexOfColumn, String columnNameOverride) {
         // try a name from the column name override
-        String columnName = null;
-        if (columnNameOverride != null) {
-            columnName = columnNameOverride;
-            if (!isAllowableColumnName(columnName)) {
-                columnName = fixColumnName(columnName);
-            }
-            if (!isAllowableColumnName(columnName)) {
-                columnName = null;
-            }
-        }
-        // try a name from the column alias
-        if (columnName == null && columnExp.getAlias() != null && !DEFAULT_COLUMN_NAME.equals(columnExp.getAlias())) {
-            columnName = columnExp.getAlias();
-            if (!isAllowableColumnName(columnName)) {
-                columnName = fixColumnName(columnName);
-            }
-            if (!isAllowableColumnName(columnName)) {
-                columnName = null;
-            }
-        }
-        // try a name derived from the column expression SQL
-        if (columnName == null && columnExp.getColumnName() != null
-                && !DEFAULT_COLUMN_NAME.equals(columnExp.getColumnName())) {
-            columnName = columnExp.getColumnName();
-            if (!isAllowableColumnName(columnName)) {
-                columnName = fixColumnName(columnName);
-            }
-            if (!isAllowableColumnName(columnName)) {
-                columnName = null;
-            }
-        }
-        // try a name derived from the column expression plan SQL
-        if (columnName == null && columnExp.getSQL() != null && !DEFAULT_COLUMN_NAME.equals(columnExp.getSQL())) {
-            columnName = columnExp.getSQL();
-            if (!isAllowableColumnName(columnName)) {
-                columnName = fixColumnName(columnName);
-            }
-            if (!isAllowableColumnName(columnName)) {
-                columnName = null;
-            }
-        }
-        // go with a innocuous default name pattern
+        String columnName = getColumnName(columnNameOverride, null);
         if (columnName == null) {
-            columnName = configuration.getDefaultColumnNamePattern()
-                    .replace("$$", Integer.toString(indexOfColumn + 1));
+            // try a name from the column alias
+            columnName = getColumnName(columnExp.getAlias(), DEFAULT_COLUMN_NAME);
+            if (columnName == null) {
+                // try a name derived from the column expression SQL
+                columnName = getColumnName(columnExp.getColumnName(), DEFAULT_COLUMN_NAME);
+                if (columnName == null) {
+                    // try a name derived from the column expression plan SQL
+                    columnName = getColumnName(columnExp.getSQL(), DEFAULT_COLUMN_NAME);
+                    // go with a innocuous default name pattern
+                    if (columnName == null) {
+                        columnName = configuration.getDefaultColumnNamePattern()
+                                .replace("$$", Integer.toString(indexOfColumn + 1));
+                    }
+                }
+            }
         }
         if (existingColumnNames.contains(columnName) && configuration.isGenerateUniqueColumnNames()) {
             columnName = generateUniqueName(columnName);
@@ -110,6 +82,21 @@ public class ColumnNamer {
         return columnName;
     }
 
+    private String getColumnName(String proposedName, String disallowedName) {
+        String columnName = null;
+        if (proposedName != null && !proposedName.equals(disallowedName)) {
+            if (isAllowableColumnName(proposedName)) {
+                columnName = proposedName;
+            } else {
+                proposedName = fixColumnName(proposedName);
+                if (isAllowableColumnName(proposedName)) {
+                    columnName = proposedName;
+                }
+            }
+        }
+        return columnName;
+    }
+
     private String generateUniqueName(String columnName) {
         String newColumnName = columnName;
         int loopCount = 2;
@@ -124,26 +111,31 @@ public class ColumnNamer {
     }
 
     private boolean isAllowableColumnName(String proposedName) {
-
         // check null
         if (proposedName == null) {
             return false;
         }
         // check size limits
-        if (proposedName.length() > configuration.getMaxIdentiferLength() || proposedName.length() == 0) {
+        int length = proposedName.length();
+        if (length > configuration.getMaxIdentiferLength() || length == 0) {
             return false;
         }
-        Matcher match = configuration.getCompiledRegularExpressionMatchAllowed().matcher(proposedName);
-        return match.matches();
+        Pattern allowed = configuration.getCompiledRegularExpressionMatchAllowed();
+        return allowed == null || allowed.matcher(proposedName).matches();
     }
 
     private String fixColumnName(String proposedName) {
-        Matcher match = configuration.getCompiledRegularExpressionMatchDisallowed().matcher(proposedName);
-        proposedName = match.replaceAll("");
+        Pattern disallowed = configuration.getCompiledRegularExpressionMatchDisallowed();
+        if (disallowed == null) {
+            proposedName = StringUtils.replaceAll(proposedName, "\u0000", "");
+        } else {
+            proposedName = disallowed.matcher(proposedName).replaceAll("");
+        }
 
         // check size limits - then truncate
-        if (proposedName.length() > configuration.getMaxIdentiferLength()) {
-            proposedName = proposedName.substring(0, configuration.getMaxIdentiferLength());
+        int length = proposedName.length(), maxLength = configuration.getMaxIdentiferLength();
+        if (length > maxLength) {
+            proposedName = proposedName.substring(0, maxLength);
         }
 
         return proposedName;

h2/src/main/org/h2/util/ColumnNamerConfiguration.java

@@ -40,8 +40,7 @@ public class ColumnNamerConfiguration {
         this.defaultColumnNamePattern = defaultColumnNamePattern;
         this.generateUniqueColumnNames = generateUniqueColumnNames;
 
-        compiledRegularExpressionMatchAllowed = Pattern.compile(regularExpressionMatchAllowed);
-        compiledRegularExpressionMatchDisallowed = Pattern.compile(regularExpressionMatchDisallowed);
+        recompilePatterns();
     }
 
     public int getMaxIdentiferLength() {
@@ -80,6 +79,11 @@ public class ColumnNamerConfiguration {
         this.defaultColumnNamePattern = defaultColumnNamePattern;
     }
 
+    /**
+     * Returns compiled pattern for allowed names.
+     *
+     * @return compiled pattern, or null for default
+     */
     public Pattern getCompiledRegularExpressionMatchAllowed() {
         return compiledRegularExpressionMatchAllowed;
     }
@@ -88,6 +92,11 @@ public class ColumnNamerConfiguration {
         this.compiledRegularExpressionMatchAllowed = compiledRegularExpressionMatchAllowed;
     }
 
+    /**
+     * Returns compiled pattern for disallowed names.
+     *
+     * @return compiled pattern, or null for default
+     */
     public Pattern getCompiledRegularExpressionMatchDisallowed() {
         return compiledRegularExpressionMatchDisallowed;
     }
@@ -138,8 +147,11 @@ public class ColumnNamerConfiguration {
     private void recompilePatterns() {
         try {
             // recompile RE patterns
-            setCompiledRegularExpressionMatchAllowed(Pattern.compile(getRegularExpressionMatchAllowed()));
-            setCompiledRegularExpressionMatchDisallowed(Pattern.compile(getRegularExpressionMatchDisallowed()));
+            setCompiledRegularExpressionMatchAllowed(
+                    regularExpressionMatchAllowed != null ? Pattern.compile(regularExpressionMatchAllowed) : null);
+            setCompiledRegularExpressionMatchDisallowed(
+                    regularExpressionMatchDisallowed != null ? Pattern.compile(regularExpressionMatchDisallowed)
+                            : null);
         } catch (Exception e) {
             configure(REGULAR);
             throw e;
@@ -147,7 +159,7 @@ public class ColumnNamerConfiguration {
     }
 
     public static ColumnNamerConfiguration getDefault() {
-        return new ColumnNamerConfiguration(Integer.MAX_VALUE, "(?m)(?s).+", "(?m)(?s)[\\x00]", "_UNNAMED_$$", false);
+        return new ColumnNamerConfiguration(Integer.MAX_VALUE, null, null, "_UNNAMED_$$", false);
     }
 
     private static String unquoteString(String s) {
@@ -220,8 +232,8 @@ public class ColumnNamerConfiguration {
         case Ignite:
             default:
             setMaxIdentiferLength(Integer.MAX_VALUE);
-            setRegularExpressionMatchAllowed("(?m)(?s).+");
-            setRegularExpressionMatchDisallowed("(?m)(?s)[\\x00]");
+            setRegularExpressionMatchAllowed(null);
+            setRegularExpressionMatchDisallowed(null);
             setDefaultColumnNamePattern("_UNNAMED_$$");
             setGenerateUniqueColumnNames(false);
             break;

h2/src/main/org/h2/util/DateTimeUtils.java

@@ -1511,18 +1511,17 @@ public class DateTimeUtils {
     /**
      * Formats timestamp with time zone as string.
      *
+     * @param buff the target string builder
      * @param dateValue the year-month-day bit field
      * @param timeNanos nanoseconds since midnight
      * @param timeZoneOffsetMins the time zone offset in minutes
-     * @return formatted string
      */
-    public static String timestampTimeZoneToString(long dateValue, long timeNanos, short timeZoneOffsetMins) {
-        StringBuilder buff = new StringBuilder(ValueTimestampTimeZone.MAXIMUM_PRECISION);
+    public static void appendTimestampTimeZone(StringBuilder buff, long dateValue, long timeNanos,
+            short timeZoneOffsetMins) {
         appendDate(buff, dateValue);
         buff.append(' ');
         appendTime(buff, timeNanos);
         appendTimeZone(buff, timeZoneOffsetMins);
-        return buff.toString();
     }
 
     /**

h2/src/main/org/h2/util/IntervalUtils.java

@@ -383,8 +383,11 @@ public class IntervalUtils {
     }
 
     /**
-     * Formats interval as a string.
+     * Formats interval as a string and appends it to a specified string
+     * builder.
      *
+     * @param buff
+     *            string builder to append to
      * @param qualifier
      *            qualifier of the interval
      * @param negative
@@ -393,12 +396,11 @@ public class IntervalUtils {
      *            the value of leading field
      * @param remaining
      *            the value of all remaining fields
-     * @return string representation of the specified interval
+     * @return the specified string builder
      */
-    public static String intervalToString(IntervalQualifier qualifier, boolean negative, long leading, long remaining)
-    {
-        StringBuilder buff = new StringBuilder().append("INTERVAL ");
-        buff.append('\'');
+    public static StringBuilder appendInterval(StringBuilder buff, IntervalQualifier qualifier, boolean negative,
+            long leading, long remaining) {
+        buff.append("INTERVAL '");
         if (negative) {
             buff.append('-');
         }
@@ -453,8 +455,7 @@ public class IntervalUtils {
             appendSecondsWithNanos(buff, remaining);
             break;
         }
-        buff.append("' ").append(qualifier);
-        return buff.toString();
+        return buff.append("' ").append(qualifier);
     }
 
     private static void appendSecondsWithNanos(StringBuilder buff, long nanos) {

h2/src/main/org/h2/util/NetUtils.java

@@ -155,7 +155,7 @@ public class NetUtils {
      */
     private static InetAddress getBindAddress() throws UnknownHostException {
         String host = SysProperties.BIND_ADDRESS;
-        if (host == null || host.length() == 0) {
+        if (host == null || host.isEmpty()) {
             return null;
         }
         synchronized (NetUtils.class) {

h2/src/main/org/h2/util/ToChar.java

@@ -362,13 +362,14 @@ public class ToChar {
         }
         int i = idx + 1;
         boolean allZeroes = true;
-        for (; i < numberStr.length(); i++) {
+        int length = numberStr.length();
+        for (; i < length; i++) {
             if (numberStr.charAt(i) != '0') {
                 allZeroes = false;
                 break;
             }
         }
-        final char[] zeroes = new char[allZeroes ? numberStr.length() - idx - 1: i - 1 - idx];
+        final char[] zeroes = new char[allZeroes ? length - idx - 1: i - 1 - idx];
         Arrays.fill(zeroes, '0');
         return String.valueOf(zeroes);
     }
@@ -688,7 +689,7 @@ public class ToChar {
         StringBuilder output = new StringBuilder();
         boolean fillMode = true;
 
-        for (int i = 0; i < format.length();) {
+        for (int i = 0, length = format.length(); i < length;) {
 
             Capitalization cap;
 

h2/src/main/org/h2/util/ToDateParser.java

@@ -249,7 +249,7 @@ public class ToDateParser {
     }
 
     private boolean hasToParseData() {
-        return formatStr.length() > 0;
+        return !formatStr.isEmpty();
     }
 
     private void removeFirstChar() {

h2/src/main/org/h2/util/ToDateTokenizer.java

@@ -651,7 +651,7 @@ class ToDateTokenizer {
          * @return the list of tokens, or {@code null}
          */
         static List<FormatTokenEnum> getTokensInQuestion(String formatStr) {
-            if (formatStr != null && formatStr.length() > 0) {
+            if (formatStr != null && !formatStr.isEmpty()) {
                 char key = Character.toUpperCase(formatStr.charAt(0));
                 if (key >= 'A' && key <= 'Y') {
                     List<FormatTokenEnum>[] tokens = TOKENS;

h2/src/main/org/h2/value/CompareMode.java

@@ -222,12 +222,13 @@ public class CompareMode implements Comparator<Value> {
         } else if (name.startsWith(CHARSET)) {
             return new CharsetCollator(Charset.forName(name.substring(CHARSET.length())));
         }
-        if (name.length() == 2) {
+        int length = name.length();
+        if (length == 2) {
             Locale locale = new Locale(StringUtils.toLowerEnglish(name), "");
             if (compareLocaleNames(locale, name)) {
                 result = Collator.getInstance(locale);
             }
-        } else if (name.length() == 5) {
+        } else if (length == 5) {
             // LL_CC (language_country)
             int idx = name.indexOf('_');
             if (idx >= 0) {