Merge pull request #863 from igor-suhorukov/master

Polish: use isEmpty() to check whether the collection is empty or not.

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

@@ -548,7 +548,7 @@ public class Parser {
     }
 
     private DbException getSyntaxError() {
-        if (expectedList == null || expectedList.size() == 0) {
+        if (expectedList == null || expectedList.isEmpty()) {
             return DbException.getSyntaxError(sqlCommand, parseIndex);
         }
         StatementBuilder buff = new StatementBuilder();
@@ -3023,7 +3023,7 @@ public class Parser {
                     // this can occur when parsing expressions only (for
                     // example check constraints)
                     throw getSyntaxError();
-                } else if (parameters.size() > 0) {
+                } else if (!parameters.isEmpty()) {
                     throw DbException
                             .get(ErrorCode.CANNOT_MIX_INDEXED_AND_UNINDEXED_PARAMS);
                 }
@@ -4725,7 +4725,7 @@ public class Parser {
                 int scale, displaySize;
                 Column column;
                 String columnName = "C" + (i + 1);
-                if (rows.size() == 0) {
+                if (rows.isEmpty()) {
                     if (type == Value.UNKNOWN) {
                         type = Value.STRING;
                     }

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

@@ -119,7 +119,7 @@ public class CreateTable extends SchemaCommand {
         }
         if (asQuery != null) {
             asQuery.prepare();
-            if (data.columns.size() == 0) {
+            if (data.columns.isEmpty()) {
                 generateColumnsFromQuery();
             } else if (data.columns.size() != asQuery.getColumnCount()) {
                 throw DbException.get(ErrorCode.COLUMN_COUNT_DOES_NOT_MATCH);

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

@@ -98,7 +98,7 @@ public class CreateView extends SchemaCommand {
             querySQL = selectSQL;
         } else {
             ArrayList<Parameter> params = select.getParameters();
-            if (params != null && params.size() > 0) {
+            if (params != null && !params.isEmpty()) {
                 throw DbException.getUnsupportedException("parameters in views");
             }
             querySQL = select.getPlanSQL();

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

@@ -77,7 +77,7 @@ public class DropTable extends SchemaCommand {
             if (dropAction == ConstraintActionType.RESTRICT) {
                 StatementBuilder buff = new StatementBuilder();
                 CopyOnWriteArrayList<TableView> dependentViews = table.getDependentViews();
-                if (dependentViews != null && dependentViews.size() > 0) {
+                if (dependentViews != null && !dependentViews.isEmpty()) {
                     for (TableView v : dependentViews) {
                         buff.appendExceptFirst(", ");
                         buff.append(v.getName());
@@ -86,7 +86,7 @@ public class DropTable extends SchemaCommand {
                 if (session.getDatabase()
                         .getSettings().standardDropTableRestrict) {
                     final List<Constraint> constraints = table.getConstraints();
-                    if (constraints != null && constraints.size() > 0) {
+                    if (constraints != null && !constraints.isEmpty()) {
                         for (Constraint c : constraints) {
                             if (c.getTable() != table) {
                                 buff.appendExceptFirst(", ");

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

@@ -243,7 +243,7 @@ public class Insert extends Prepared implements ResultTarget {
         if (sortedInsertMode) {
             buff.append("SORTED ");
         }
-        if (list.size() > 0) {
+        if (!list.isEmpty()) {
             buff.append("VALUES ");
             int row = 0;
             if (list.size() > 1) {
@@ -274,14 +274,14 @@ public class Insert extends Prepared implements ResultTarget {
     @Override
     public void prepare() {
         if (columns == null) {
-            if (list.size() > 0 && list.get(0).length == 0) {
+            if (!list.isEmpty() && list.get(0).length == 0) {
                 // special case where table is used as a sequence
                 columns = new Column[0];
             } else {
                 columns = table.getColumns();
             }
         }
-        if (list.size() > 0) {
+        if (!list.isEmpty()) {
             for (Expression[] expr : list) {
                 if (expr.length != columns.length) {
                     throw DbException.get(ErrorCode.COLUMN_COUNT_DOES_NOT_MATCH);

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

@@ -84,7 +84,7 @@ public class Merge extends Prepared {
         session.getUser().checkRight(targetTable, Right.INSERT);
         session.getUser().checkRight(targetTable, Right.UPDATE);
         setCurrentRowNumber(0);
-        if (valuesExpressionList.size() > 0) {
+        if (!valuesExpressionList.isEmpty()) {
             // process values in list
             count = 0;
             for (int x = 0, size = valuesExpressionList.size(); x < size; x++) {
@@ -221,7 +221,7 @@ public class Merge extends Prepared {
             buff.append(')');
         }
         buff.append('\n');
-        if (valuesExpressionList.size() > 0) {
+        if (!valuesExpressionList.isEmpty()) {
             buff.append("VALUES ");
             int row = 0;
             for (Expression[] expr : valuesExpressionList) {
@@ -249,14 +249,14 @@ public class Merge extends Prepared {
     @Override
     public void prepare() {
         if (columns == null) {
-            if (valuesExpressionList.size() > 0 && valuesExpressionList.get(0).length == 0) {
+            if (!valuesExpressionList.isEmpty() && valuesExpressionList.get(0).length == 0) {
                 // special case where table is used as a sequence
                 columns = new Column[0];
             } else {
                 columns = targetTable.getColumns();
             }
         }
-        if (valuesExpressionList.size() > 0) {
+        if (!valuesExpressionList.isEmpty()) {
             for (Expression[] expr : valuesExpressionList) {
                 if (expr.length != columns.length) {
                     throw DbException.get(ErrorCode.COLUMN_COUNT_DOES_NOT_MATCH);

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

@@ -315,7 +315,7 @@ public class MergeUsing extends Prepared {
             buff.append(')');
         }
         buff.append('\n');
-        if (valuesExpressionList.size() > 0) {
+        if (!valuesExpressionList.isEmpty()) {
             buff.append("VALUES ");
             int row = 0;
             for (Expression[] expr : valuesExpressionList) {
@@ -376,7 +376,7 @@ public class MergeUsing extends Prepared {
         onCondition.createIndexConditions(session, targetTableFilter);
 
         if (columns == null) {
-            if (valuesExpressionList.size() > 0
+            if (!valuesExpressionList.isEmpty()
                     && valuesExpressionList.get(0).length == 0) {
                 // special case where table is used as a sequence
                 columns = new Column[0];
@@ -384,7 +384,7 @@ public class MergeUsing extends Prepared {
                 columns = targetTable.getColumns();
             }
         }
-        if (valuesExpressionList.size() > 0) {
+        if (!valuesExpressionList.isEmpty()) {
             for (Expression[] expr : valuesExpressionList) {
                 if (expr.length != columns.length) {
                     throw DbException

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

@@ -82,7 +82,7 @@ public class Replace extends Prepared {
         session.getUser().checkRight(table, Right.INSERT);
         session.getUser().checkRight(table, Right.UPDATE);
         setCurrentRowNumber(0);
-        if (list.size() > 0) {
+        if (!list.isEmpty()) {
             count = 0;
             for (int x = 0, size = list.size(); x < size; x++) {
                 setCurrentRowNumber(x + 1);
@@ -208,7 +208,7 @@ public class Replace extends Prepared {
         }
         buff.append(')');
         buff.append('\n');
-        if (list.size() > 0) {
+        if (!list.isEmpty()) {
             buff.append("VALUES ");
             int row = 0;
             for (Expression[] expr : list) {
@@ -236,14 +236,14 @@ public class Replace extends Prepared {
     @Override
     public void prepare() {
         if (columns == null) {
-            if (list.size() > 0 && list.get(0).length == 0) {
+            if (!list.isEmpty() && list.get(0).length == 0) {
                 // special case where table is used as a sequence
                 columns = new Column[0];
             } else {
                 columns = table.getColumns();
             }
         }
-        if (list.size() > 0) {
+        if (!list.isEmpty()) {
             for (Expression[] expr : list) {
                 if (expr.length != columns.length) {
                     throw DbException.get(ErrorCode.COLUMN_COUNT_DOES_NOT_MATCH);

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

@@ -1212,7 +1212,7 @@ public class Database implements DataHandler {
                 trace.info("disconnecting session #{0}", session.getId());
             }
         }
-        if (userSessions.size() == 0 &&
+        if (userSessions.isEmpty() &&
                 session != systemSession && session != lobSession) {
             if (closeDelay == 0) {
                 close(false);
@@ -1275,7 +1275,7 @@ public class Database implements DataHandler {
             }
             closing = true;
             stopServer();
-            if (userSessions.size() > 0) {
+            if (!userSessions.isEmpty()) {
                 if (!fromShutdownHook) {
                     return;
                 }
@@ -1290,7 +1290,7 @@ public class Database implements DataHandler {
                 // set it to null, to make sure it's called only once
                 eventListener = null;
                 e.closingDatabase();
-                if (userSessions.size() > 0) {
+                if (!userSessions.isEmpty()) {
                     // if a connection was opened, we can't close the database
                     return;
                 }

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

@@ -63,7 +63,7 @@ public class Engine implements SessionFactory {
             }
             database = new Database(ci, cipher);
             opened = true;
-            if (database.getAllUsers().size() == 0) {
+            if (database.getAllUsers().isEmpty()) {
                 // users is the last thing we add, so if no user is around,
                 // the database is new (or not initialized correctly)
                 user = new User(database, database.allocateObjectId(),

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

@@ -163,7 +163,7 @@ public class FunctionAlias extends SchemaObjectBase {
                 list.add(javaMethod);
             }
         }
-        if (list.size() == 0) {
+        if (list.isEmpty()) {
             throw DbException.get(
                     ErrorCode.PUBLIC_STATIC_JAVA_METHOD_NOT_FOUND_1,
                     methodName + " (" + className + ")");

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

@@ -251,7 +251,7 @@ public class Session extends SessionWithState {
         }
     }
     public String getParsingCreateViewName() {
-        if (viewNameStack.size() == 0) {
+        if (viewNameStack.isEmpty()) {
             return null;
         }
         return viewNameStack.peek();
@@ -652,7 +652,7 @@ public class Session extends SessionWithState {
             // increment the data mod count, so that other sessions
             // see the changes
             // TODO should not rely on locking
-            if (locks.size() > 0) {
+            if (!locks.isEmpty()) {
                 for (int i = 0, size = locks.size(); i < size; i++) {
                     Table t = locks.get(i);
                     if (t instanceof MVTable) {
@@ -726,10 +726,10 @@ public class Session extends SessionWithState {
             }
             temporaryLobs.clear();
         }
-        if (temporaryResultLobs != null && temporaryResultLobs.size() > 0) {
+        if (temporaryResultLobs != null && !temporaryResultLobs.isEmpty()) {
             long keepYoungerThan = System.nanoTime() -
                     TimeUnit.MILLISECONDS.toNanos(database.getSettings().lobTimeout);
-            while (temporaryResultLobs.size() > 0) {
+            while (!temporaryResultLobs.isEmpty()) {
                 TimeoutValue tv = temporaryResultLobs.getFirst();
                 if (onTimeout && tv.created >= keepYoungerThan) {
                     break;
@@ -743,7 +743,7 @@ public class Session extends SessionWithState {
     }
 
     private void checkCommitRollback() {
-        if (commitOrRollbackDisabled && locks.size() > 0) {
+        if (commitOrRollbackDisabled && !locks.isEmpty()) {
             throw DbException.get(ErrorCode.COMMIT_ROLLBACK_NOT_ALLOWED);
         }
     }
@@ -783,7 +783,7 @@ public class Session extends SessionWithState {
             transaction.commit();
             transaction = null;
         }
-        if (locks.size() > 0 || needCommit) {
+        if (!locks.isEmpty() || needCommit) {
             database.commit(this);
         }
         cleanTempTables(false);
@@ -990,7 +990,7 @@ public class Session extends SessionWithState {
                 DbException.throwInternalError();
             }
         }
-        if (locks.size() > 0) {
+        if (!locks.isEmpty()) {
             // don't use the enhanced for loop to save memory
             for (int i = 0, size = locks.size(); i < size; i++) {
                 Table t = locks.get(i);

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

@@ -482,7 +482,7 @@ public class SessionRemote extends SessionWithState implements DataHandler {
     public void removeServer(IOException e, int i, int count) {
         trace.debug(e, "removing server because of exception");
         transferList.remove(i);
-        if (transferList.size() == 0 && autoReconnect(count)) {
+        if (transferList.isEmpty() && autoReconnect(count)) {
             return;
         }
         checkClosed();
@@ -653,7 +653,7 @@ public class SessionRemote extends SessionWithState implements DataHandler {
 
     @Override
     public boolean isClosed() {
-        return transferList == null || transferList.size() == 0;
+        return transferList == null || transferList.isEmpty();
     }
 
     /**

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

@@ -24,7 +24,7 @@ abstract class SessionWithState implements SessionInterface {
      * Re-create the session state using the stored sessionState list.
      */
     protected void recreateSessionState() {
-        if (sessionState != null && sessionState.size() > 0) {
+        if (sessionState != null && !sessionState.isEmpty()) {
             sessionStateUpdating = true;
             try {
                 for (String sql : sessionState) {

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

@@ -328,7 +328,7 @@ public class Aggregate extends Expression {
         Value v = data.getValue(session.getDatabase(), dataType, distinct);
         if (type == AggregateType.GROUP_CONCAT) {
             ArrayList<Value> list = ((AggregateDataGroupConcat) data).getList();
-            if (list == null || list.size() == 0) {
+            if (list == null || list.isEmpty()) {
                 return ValueNull.INSTANCE;
             }
             if (groupConcatOrderList != null) {

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

@@ -624,7 +624,7 @@ public class FullText {
                 }
             }
         }
-        if (rIds == null || rIds.size() == 0) {
+        if (rIds == null || rIds.isEmpty()) {
             return result;
         }
         PreparedStatement prepSelectRowById = setting.prepare(conn, SELECT_ROW_BY_ID);
@@ -913,7 +913,7 @@ public class FullText {
             for (int i = 0; rs.next(); i++) {
                 columnTypes[i] = rs.getInt("DATA_TYPE");
             }
-            if (keyList.size() == 0) {
+            if (keyList.isEmpty()) {
                 rs = meta.getPrimaryKeys(null,
                         StringUtils.escapeMetaDataPattern(schemaName),
                         tableName);
@@ -921,7 +921,7 @@ public class FullText {
                     keyList.add(rs.getString("COLUMN_NAME"));
                 }
             }
-            if (keyList.size() == 0) {
+            if (keyList.isEmpty()) {
                 throw throwException("No primary key for table " + tableName);
             }
             ArrayList<String> indexList = New.arrayList();
@@ -938,7 +938,7 @@ public class FullText {
                     Collections.addAll(indexList, StringUtils.arraySplit(columns, ',', true));
                 }
             }
-            if (indexList.size() == 0) {
+            if (indexList.isEmpty()) {
                 indexList.addAll(columnList);
             }
             index.keys = new int[keyList.size()];

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

@@ -505,7 +505,7 @@ public class FullTextLucene extends FullText {
             for (int i = 0; rs.next(); i++) {
                 columnTypes[i] = rs.getInt("DATA_TYPE");
             }
-            if (keyList.size() == 0) {
+            if (keyList.isEmpty()) {
                 rs = meta.getPrimaryKeys(null,
                         StringUtils.escapeMetaDataPattern(schemaName),
                         tableName);
@@ -513,7 +513,7 @@ public class FullTextLucene extends FullText {
                     keyList.add(rs.getString("COLUMN_NAME"));
                 }
             }
-            if (keyList.size() == 0) {
+            if (keyList.isEmpty()) {
                 throw throwException("No primary key for table " + tableName);
             }
             ArrayList<String> indexList = New.arrayList();
@@ -530,7 +530,7 @@ public class FullTextLucene extends FullText {
                             StringUtils.arraySplit(cols, ',', true));
                 }
             }
-            if (indexList.size() == 0) {
+            if (indexList.isEmpty()) {
                 indexList.addAll(columnList);
             }
             keys = new int[keyList.size()];

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

@@ -202,7 +202,7 @@ public class JdbcXAConnection extends TraceObject implements XAConnection,
             }
             rs.close();
             Xid[] result = list.toArray(new Xid[0]);
-            if (list.size() > 0) {
+            if (!list.isEmpty()) {
                 prepared = true;
             }
             return result;

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

@@ -241,7 +241,7 @@ public class Trace {
      */
     public static String formatParams(
             ArrayList<? extends ParameterInterface> parameters) {
-        if (parameters.size() == 0) {
+        if (parameters.isEmpty()) {
             return "";
         }
         StatementBuilder buff = new StatementBuilder();

h2/src/main/org/h2/mvstore/MVStore.java

@@ -1479,7 +1479,7 @@ public final class MVStore {
             for (Chunk c : modified) {
                 meta.put(Chunk.getMetaKey(c.id), c.asString());
             }
-            if (modified.size() == 0) {
+            if (modified.isEmpty()) {
                 break;
             }
         }
@@ -1782,7 +1782,7 @@ public final class MVStore {
             synchronized (this) {
                 old = compactGetOldChunks(targetFillRate, write);
             }
-            if (old == null || old.size() == 0) {
+            if (old == null || old.isEmpty()) {
                 return false;
             }
             compactRewrite(old);
@@ -1838,7 +1838,7 @@ public final class MVStore {
             c.collectPriority = (int) (c.getFillRate() * 1000 / age);
             old.add(c);
         }
-        if (old.size() == 0) {
+        if (old.isEmpty()) {
             return null;
         }
 
@@ -2287,7 +2287,7 @@ public final class MVStore {
                 keep = c;
             }
         }
-        if (remove.size() > 0) {
+        if (!remove.isEmpty()) {
             // remove the youngest first, so we don't create gaps
             // (in case we remove many chunks)
             Collections.sort(remove, Collections.reverseOrder());

h2/src/main/org/h2/mvstore/db/MVTable.java

@@ -610,7 +610,7 @@ public class MVTable extends TableBase {
             remaining--;
         }
         sortRows(buffer, index);
-        if (bufferNames.size() > 0) {
+        if (!bufferNames.isEmpty()) {
             String mapName = store.nextTemporaryMapName();
             index.addRowsToBuffer(buffer, mapName);
             bufferNames.add(mapName);

h2/src/main/org/h2/mvstore/rtree/SpatialDataType.java

@@ -305,7 +305,7 @@ public class SpatialDataType implements DataType {
      */
     public int[] getExtremes(ArrayList<Object> list) {
         list = getNotNull(list);
-        if (list.size() == 0) {
+        if (list.isEmpty()) {
             return null;
         }
         SpatialKey bounds = (SpatialKey) createBoundingBox(list.get(0));

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

@@ -118,7 +118,7 @@ public class UpdatableRow {
     }
 
     private boolean isIndexUsable(ArrayList<String> indexColumns) {
-        if (indexColumns.size() == 0) {
+        if (indexColumns.isEmpty()) {
             return false;
         }
         for (String c : indexColumns) {

h2/src/main/org/h2/security/CipherFactory.java

@@ -182,7 +182,7 @@ public class CipherFactory {
         boolean ecdhAnonRemoved = algorithms.remove("ECDH_anon");
         if (dhAnonRemoved || ecdhAnonRemoved) {
             String string = Arrays.toString(algorithms.toArray(new String[algorithms.size()]));
-            return (algorithms.size() > 0) ? string.substring(1, string.length() - 1): "";
+            return (!algorithms.isEmpty()) ? string.substring(1, string.length() - 1): "";
         }
         return list;
     }

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

@@ -886,7 +886,7 @@ public class PgServerThread implements Runnable {
             }
             stat.execute("set search_path = PUBLIC, pg_catalog");
             HashSet<Integer> typeSet = server.getTypeSet();
-            if (typeSet.size() == 0) {
+            if (typeSet.isEmpty()) {
                 try (ResultSet rs = stat.executeQuery("select oid from pg_catalog.pg_type")) {
                     while (rs.next()) {
                         typeSet.add(rs.getInt(1));

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

@@ -98,7 +98,7 @@ public class PageParser {
                             result.append("?items?");
                             list = New.arrayList();
                         }
-                        if (list.size() == 0) {
+                        if (list.isEmpty()) {
                             parseBlockUntil("</c:forEach>");
                         }
                         for (Object o : list) {

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

@@ -1869,7 +1869,7 @@ public class WebApp {
         String setting = attributes.getProperty("name", "");
         server.removeSetting(setting);
         ArrayList<ConnectionInfo> settings = server.getSettings();
-        if (settings.size() > 0) {
+        if (!settings.isEmpty()) {
             attributes.put("setting", settings.get(0));
         }
         server.saveProperties(null);

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

@@ -206,7 +206,7 @@ class WebSession {
                     "${text.admin.notConnected}" : conn.getMetaData().getURL());
             m.put("user", conn == null ?
                     "-" : conn.getMetaData().getUserName());
-            m.put("lastQuery", commandHistory.size() == 0 ?
+            m.put("lastQuery", commandHistory.isEmpty() ?
                     "" : commandHistory.get(0));
             m.put("executing", executingStatement == null ?
                     "${text.admin.no}" : "${text.admin.yes}");

h2/src/main/org/h2/store/PageStore.java

@@ -1407,7 +1407,7 @@ public class PageStore implements CacheWriter {
         isEmpty &= log.recover(PageLog.RECOVERY_STAGE_REDO);
         boolean setReadOnly = false;
         if (!database.isReadOnly()) {
-            if (log.getInDoubtTransactions().size() == 0) {
+            if (log.getInDoubtTransactions().isEmpty()) {
                 log.recoverEnd();
                 int firstUncommittedSection = getFirstUncommittedSection();
                 log.removeUntil(firstUncommittedSection);

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

@@ -671,7 +671,7 @@ public class RegularTable extends TableBase {
                 lockExclusiveSession = null;
             }
             synchronized (database) {
-                if (lockSharedSessions.size() > 0) {
+                if (!lockSharedSessions.isEmpty()) {
                     lockSharedSessions.remove(s);
                 }
                 if (!waitingSessions.isEmpty()) {

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

@@ -529,20 +529,20 @@ public abstract class Table extends SchemaObjectBase {
 
     @Override
     public void removeChildrenAndResources(Session session) {
-        while (dependentViews.size() > 0) {
+        while (!dependentViews.isEmpty()) {
             TableView view = dependentViews.get(0);
             dependentViews.remove(0);
             database.removeSchemaObject(session, view);
         }
-        while (synonyms != null && synonyms.size() > 0) {
+        while (synonyms != null && !synonyms.isEmpty()) {
             TableSynonym synonym = synonyms.remove(0);
             database.removeSchemaObject(session, synonym);
         }
-        while (triggers != null && triggers.size() > 0) {
+        while (triggers != null && !triggers.isEmpty()) {
             TriggerObject trigger = triggers.remove(0);
             database.removeSchemaObject(session, trigger);
         }
-        while (constraints != null && constraints.size() > 0) {
+        while (constraints != null && !constraints.isEmpty()) {
             Constraint constraint = constraints.remove(0);
             database.removeSchemaObject(session, constraint);
         }
@@ -554,7 +554,7 @@ public abstract class Table extends SchemaObjectBase {
         database.removeMeta(session, getId());
         // must delete sequences later (in case there is a power failure
         // before removing the table object)
-        while (sequences != null && sequences.size() > 0) {
+        while (sequences != null && !sequences.isEmpty()) {
             Sequence sequence = sequences.remove(0);
             // only remove if no other table depends on this sequence
             // this is possible when calling ALTER TABLE ALTER COLUMN
@@ -975,8 +975,8 @@ public abstract class Table extends SchemaObjectBase {
      *  @return if there are any triggers or rows defined
      */
     public boolean fireRow() {
-        return (constraints != null && constraints.size() > 0) ||
-                (triggers != null && triggers.size() > 0);
+        return (constraints != null && !constraints.isEmpty()) ||
+                (triggers != null && !triggers.isEmpty());
     }
 
     /**

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

@@ -197,7 +197,7 @@ public class TableFilter implements ColumnResolver {
         if (select != null) {
             sortOrder = select.getSortOrder();
         }
-        if (indexConditions.size() == 0) {
+        if (indexConditions.isEmpty()) {
             item1 = new PlanItem();
             item1.setIndex(table.getScanIndex(s, null, filters, filter,
                     sortOrder, allColumnsSet));
@@ -854,7 +854,7 @@ public class TableFilter implements ColumnResolver {
                 }
             }
             planBuff.append(index.getPlanSQL());
-            if (indexConditions.size() > 0) {
+            if (!indexConditions.isEmpty()) {
                 planBuff.append(": ");
                 for (IndexCondition condition : indexConditions) {
                     planBuff.appendExceptFirst("\n    AND ");

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

@@ -173,7 +173,7 @@ public class TableLink extends Table {
         try (Statement stat = conn.getConnection().createStatement()) {
             rs = stat.executeQuery("SELECT * FROM " +
                     qualifiedTableName + " T WHERE 1=0");
-            if (columnList.size() == 0) {
+            if (columnList.isEmpty()) {
                 // alternative solution
                 ResultSetMetaData rsMeta = rs.getMetaData();
                 for (i = 0; i < rsMeta.getColumnCount();) {
@@ -501,7 +501,7 @@ public class TableLink extends Table {
                     if (trace.isDebugEnabled()) {
                         StatementBuilder buff = new StatementBuilder();
                         buff.append(getName()).append(":\n").append(sql);
-                        if (params != null && params.size() > 0) {
+                        if (params != null && !params.isEmpty()) {
                             buff.append(" {");
                             int i = 1;
                             for (Value v : params) {

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

@@ -114,7 +114,7 @@ public class Backup extends Tool {
         } else {
             list = FileLister.getDatabaseFiles(directory, db, true);
         }
-        if (list.size() == 0) {
+        if (list.isEmpty()) {
             if (!quiet) {
                 printNoDatabaseFilesFound(directory, db);
             }

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

@@ -170,7 +170,7 @@ public class ChangeFileEncryption extends Tool {
         ArrayList<String> files = FileLister.getDatabaseFiles(dir, db, true);
         FileLister.tryUnlockDatabase(files, "encryption");
         files = FileLister.getDatabaseFiles(dir, db, false);
-        if (files.size() == 0 && !quiet) {
+        if (files.isEmpty() && !quiet) {
             printNoDatabaseFilesFound(dir, db);
         }
         // first, test only if the file can be renamed

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

@@ -343,7 +343,7 @@ public class Csv implements SimpleRowSource {
             String v = readValue();
             if (v == null) {
                 if (endOfLine) {
-                    if (endOfFile || list.size() > 0) {
+                    if (endOfFile || !list.isEmpty()) {
                         break;
                     }
                 } else {

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

@@ -84,7 +84,7 @@ public class DeleteDbFiles extends Tool {
      */
     private void process(String dir, String db, boolean quiet) {
         ArrayList<String> files = FileLister.getDatabaseFiles(dir, db, true);
-        if (files.size() == 0 && !quiet) {
+        if (files.isEmpty() && !quiet) {
             printNoDatabaseFilesFound(dir, db);
         }
         for (String fileName : files) {

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

@@ -330,7 +330,7 @@ public class Recover extends Tool implements DataHandler {
 
     private void process(String dir, String db) {
         ArrayList<String> list = FileLister.getDatabaseFiles(dir, db, true);
-        if (list.size() == 0) {
+        if (list.isEmpty()) {
             printNoDatabaseFilesFound(dir, db);
         }
         for (String fileName : list) {

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

@@ -243,7 +243,7 @@ public class Shell extends Tool implements Runnable {
                         s = s.replace('\n', ' ').replace('\r', ' ');
                         println("#" + (1 + i) + ": " + s);
                     }
-                    if (history.size() > 0) {
+                    if (!history.isEmpty()) {
                         println("To re-run a statement, type the number and press and enter");
                     } else {
                         println("No history");

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

@@ -116,7 +116,7 @@ public class SimpleResultSet implements ResultSet, ResultSetMetaData,
      */
     public void addColumn(String name, int sqlType, String sqlTypeName,
             int precision, int scale) {
-        if (rows != null && rows.size() > 0) {
+        if (rows != null && !rows.isEmpty()) {
             throw new IllegalStateException(
                     "Cannot add a column after adding rows");
         }

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

@@ -71,7 +71,7 @@ public class AbbaDetector {
             System.out.println(thread + " " + indent +
                     "sync " + getObjectName(o));
         }
-        if (stack.size() > 0) {
+        if (!stack.isEmpty()) {
             markHigher(o, stack);
         }
         stack.push(o);

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

@@ -163,7 +163,7 @@ public class CacheLRU implements Cache {
             if (rc <= Constants.CACHE_MIN_RECORDS) {
                 break;
             }
-            if (changed.size() == 0) {
+            if (changed.isEmpty()) {
                 if (mem <= maxMemory) {
                     break;
                 }
@@ -209,7 +209,7 @@ public class CacheLRU implements Cache {
                 remove(check.getPos());
             }
         }
-        if (changed.size() > 0) {
+        if (!changed.isEmpty()) {
             if (!flushed) {
                 writer.flushLog();
             }

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

@@ -253,7 +253,7 @@ public class Profiler implements Runnable {
                 line = line.substring(3).trim();
                 stack.add(line);
             }
-            if (stack.size() > 0) {
+            if (!stack.isEmpty()) {
                 String[] s = stack.toArray(new String[0]);
                 list.add(s);
             }