Do not use concatenation with "" for converting non-constant numbers

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

@@ -2062,7 +2062,7 @@ public class ErrorCode {
         case FEATURE_NOT_SUPPORTED_1: return "HYC00";
         case LOCK_TIMEOUT_1: return "HYT00";
         default:
-            return "" + errorCode;
+            return Integer.toString(errorCode);
         }
     }
 

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

@@ -520,7 +520,7 @@ public abstract class Query extends Prepared {
                 }
                 idx -= 1;
                 if (idx < 0 || idx >= expressionCount) {
-                    throw DbException.get(ErrorCode.ORDER_BY_NOT_IN_RESULT, "" + (idx + 1));
+                    throw DbException.get(ErrorCode.ORDER_BY_NOT_IN_RESULT, Integer.toString(idx + 1));
                 }
             }
             index[i] = idx;

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

@@ -411,7 +411,7 @@ public class Database implements DataHandler {
                 if (now > reconnectCheckNext) {
                     if (pending) {
                         String pos = pageStore == null ?
-                                null : "" + pageStore.getWriteCountTotal();
+                                null : Long.toString(pageStore.getWriteCountTotal());
                         lock.setProperty("logPos", pos);
                         lock.save();
                     }
@@ -433,7 +433,7 @@ public class Database implements DataHandler {
                 }
             }
             String pos = pageStore == null ?
-                    null : "" + pageStore.getWriteCountTotal();
+                    null : Long.toString(pageStore.getWriteCountTotal());
             lock.setProperty("logPos", pos);
             if (pending) {
                 lock.setProperty("changePending", "true-" + Math.random());
@@ -2646,7 +2646,7 @@ public class Database implements DataHandler {
         long now = System.nanoTime();
         if (now > reconnectCheckNext + reconnectCheckDelayNs) {
             if (SysProperties.CHECK && checkpointAllowed < 0) {
-                DbException.throwInternalError("" + checkpointAllowed);
+                DbException.throwInternalError(Integer.toString(checkpointAllowed));
             }
             synchronized (reconnectSync) {
                 if (checkpointAllowed > 0) {
@@ -2716,7 +2716,7 @@ public class Database implements DataHandler {
             if (reconnectModified(true)) {
                 checkpointAllowed++;
                 if (SysProperties.CHECK && checkpointAllowed > 20) {
-                    throw DbException.throwInternalError("" + checkpointAllowed);
+                    throw DbException.throwInternalError(Integer.toString(checkpointAllowed));
                 }
                 return true;
             }
@@ -2738,7 +2738,7 @@ public class Database implements DataHandler {
             checkpointAllowed--;
         }
         if (SysProperties.CHECK && checkpointAllowed < 0) {
-            throw DbException.throwInternalError("" + checkpointAllowed);
+            throw DbException.throwInternalError(Integer.toString(checkpointAllowed));
         }
     }
 

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

@@ -75,7 +75,7 @@ public class Right extends DbObjectBase {
 
     public Right(Database db, int id, RightOwner grantee, int grantedRight,
             DbObject grantedObject) {
-        initDbObjectBase(db, id, "" + id, Trace.USER);
+        initDbObjectBase(db, id, Integer.toString(id), Trace.USER);
         this.grantee = grantee;
         this.grantedRight = grantedRight;
         this.grantedObject = grantedObject;

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

@@ -47,7 +47,7 @@ public class SettingsBase {
      * @return the setting
      */
     protected int get(String key, int defaultValue) {
-        String s = get(key, "" + defaultValue);
+        String s = get(key, Integer.toString(defaultValue));
         try {
             return Integer.decode(s);
         } catch (NumberFormatException e) {

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

@@ -333,7 +333,7 @@ public class CompareLike extends Condition {
                 }
                 return false;
             default:
-                DbException.throwInternalError("" + types[pi]);
+                DbException.throwInternalError(Integer.toString(types[pi]));
             }
         }
         return si == sLen;

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

@@ -557,7 +557,7 @@ public class Function extends Expression implements FunctionCall {
         } else {
             if (index >= args.length) {
                 throw DbException.get(ErrorCode.INVALID_PARAMETER_COUNT_2,
-                        info.name, "" + args.length);
+                        info.name, Integer.toString(args.length));
             }
             args[index] = param;
         }
@@ -2165,7 +2165,7 @@ public class Function extends Expression implements FunctionCall {
             if (len > 0 && args[len - 1] == null) {
                 throw DbException.get(
                         ErrorCode.INVALID_PARAMETER_COUNT_2,
-                        info.name, "" + len);
+                        info.name, Integer.toString(len));
             }
         }
     }

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

@@ -100,7 +100,7 @@ public class Wildcard extends Expression {
         if (visitor.getType() == ExpressionVisitor.QUERY_COMPARABLE) {
             return true;
         }
-        throw DbException.throwInternalError("" + visitor.getType());
+        throw DbException.throwInternalError(Integer.toString(visitor.getType()));
     }
 
     @Override

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

@@ -176,7 +176,7 @@ public class PageBtreeLeaf extends PageBtree {
         written = false;
         changeCount = index.getPageStore().getChangeCount();
         if (entryCount <= 0) {
-            DbException.throwInternalError("" + entryCount);
+            DbException.throwInternalError(Integer.toString(entryCount));
         }
         int startNext = at > 0 ? offsets[at - 1] : index.getPageStore().getPageSize();
         int rowLength = startNext - offsets[at];

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

@@ -474,7 +474,7 @@ public class PageBtreeNode extends PageBtree {
         written = false;
         changeCount = index.getPageStore().getChangeCount();
         if (entryCount < 0) {
-            DbException.throwInternalError("" + entryCount);
+            DbException.throwInternalError(Integer.toString(entryCount));
         }
         if (entryCount > i) {
             int startNext = i > 0 ? offsets[i - 1] : index.getPageStore().getPageSize();

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

@@ -220,7 +220,7 @@ public class PageDataLeaf extends PageData {
         if (offset < start) {
             writtenData = false;
             if (entryCount > 1) {
-                DbException.throwInternalError("" + entryCount);
+                DbException.throwInternalError(Integer.toString(entryCount));
             }
             // need to write the overflow page id
             start += 4;
@@ -283,7 +283,7 @@ public class PageDataLeaf extends PageData {
         }
         entryCount--;
         if (entryCount < 0) {
-            DbException.throwInternalError("" + entryCount);
+            DbException.throwInternalError(Integer.toString(entryCount));
         }
         if (firstOverflowPageId != 0) {
             start -= 4;

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

@@ -388,7 +388,7 @@ public class PageDataNode extends PageData {
         entryCount--;
         length -= 4 + Data.getVarLongLen(keys[removedKeyIndex]);
         if (entryCount < 0) {
-            DbException.throwInternalError("" + entryCount);
+            DbException.throwInternalError(Integer.toString(entryCount));
         }
         keys = remove(keys, entryCount + 1, removedKeyIndex);
         childPageIds = remove(childPageIds, entryCount + 2, i);

h2/src/main/org/h2/server/TcpServerThread.java

@@ -91,15 +91,15 @@ public class TcpServerThread implements Runnable {
                 int minClientVersion = transfer.readInt();
                 if (minClientVersion < 6) {
                     throw DbException.get(ErrorCode.DRIVER_VERSION_ERROR_2,
-                            "" + minClientVersion, "" + Constants.TCP_PROTOCOL_VERSION_MIN_SUPPORTED);
+                            Integer.toString(minClientVersion), "" + Constants.TCP_PROTOCOL_VERSION_MIN_SUPPORTED);
                 }
                 int maxClientVersion = transfer.readInt();
                 if (maxClientVersion < Constants.TCP_PROTOCOL_VERSION_MIN_SUPPORTED) {
                     throw DbException.get(ErrorCode.DRIVER_VERSION_ERROR_2,
-                            "" + maxClientVersion, "" + Constants.TCP_PROTOCOL_VERSION_MIN_SUPPORTED);
+                            Integer.toString(maxClientVersion), "" + Constants.TCP_PROTOCOL_VERSION_MIN_SUPPORTED);
                 } else if (minClientVersion > Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED) {
                     throw DbException.get(ErrorCode.DRIVER_VERSION_ERROR_2,
-                            "" + minClientVersion, "" + Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED);
+                            Integer.toString(minClientVersion), "" + Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED);
                 }
                 if (maxClientVersion >= Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED) {
                     clientVersion = Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED;

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

@@ -338,8 +338,8 @@ public class WebApp {
     }
 
     private String admin() {
-        session.put("port", "" + server.getPort());
-        session.put("allowOthers", "" + server.getAllowOthers());
+        session.put("port", Integer.toString(server.getPort()));
+        session.put("allowOthers", Boolean.toString(server.getAllowOthers()));
         session.put("ssl", String.valueOf(server.getSSL()));
         session.put("sessions", server.getSessions());
         return "admin.jsp";
@@ -1172,16 +1172,16 @@ public class WebApp {
             SimpleResultSet rs = new SimpleResultSet();
             rs.addColumn("Type", Types.VARCHAR, 0, 0);
             rs.addColumn("KB", Types.VARCHAR, 0, 0);
-            rs.addRow("Used Memory", "" + Utils.getMemoryUsed());
-            rs.addRow("Free Memory", "" + Utils.getMemoryFree());
+            rs.addRow("Used Memory", Integer.toString(Utils.getMemoryUsed()));
+            rs.addRow("Free Memory", Integer.toString(Utils.getMemoryFree()));
             return rs;
         } else if (isBuiltIn(sql, "@info")) {
             SimpleResultSet rs = new SimpleResultSet();
             rs.addColumn("KEY", Types.VARCHAR, 0, 0);
             rs.addColumn("VALUE", Types.VARCHAR, 0, 0);
             rs.addRow("conn.getCatalog", conn.getCatalog());
-            rs.addRow("conn.getAutoCommit", "" + conn.getAutoCommit());
-            rs.addRow("conn.getTransactionIsolation", "" + conn.getTransactionIsolation());
+            rs.addRow("conn.getAutoCommit", Boolean.toString(conn.getAutoCommit()));
+            rs.addRow("conn.getTransactionIsolation", Integer.toString(conn.getTransactionIsolation()));
             rs.addRow("conn.getWarnings", "" + conn.getWarnings());
             String map;
             try {
@@ -1190,8 +1190,8 @@ public class WebApp {
                 map = e.toString();
             }
             rs.addRow("conn.getTypeMap", "" + map);
-            rs.addRow("conn.isReadOnly", "" + conn.isReadOnly());
-            rs.addRow("conn.getHoldability", "" + conn.getHoldability());
+            rs.addRow("conn.isReadOnly", Boolean.toString(conn.isReadOnly()));
+            rs.addRow("conn.getHoldability", Integer.toString(conn.getHoldability()));
             addDatabaseMetaData(rs, meta);
             return rs;
         } else if (isBuiltIn(sql, "@attributes")) {
@@ -1328,7 +1328,7 @@ public class WebApp {
             } else if (isBuiltIn(sql, "@maxrows")) {
                 int maxrows = (int) Double.parseDouble(
                         sql.substring("@maxrows".length()).trim());
-                session.put("maxrows", "" + maxrows);
+                session.put("maxrows", Integer.toString(maxrows));
                 return "${text.result.maxrowsSet}";
             } else if (isBuiltIn(sql, "@parameter_meta")) {
                 sql = sql.substring("@parameter_meta".length()).trim();

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

@@ -672,14 +672,11 @@ public class WebServer implements Service {
                 Properties old = loadProperties();
                 prop = new SortedProperties();
                 prop.setProperty("webPort",
-                        "" + SortedProperties.getIntProperty(old,
-                        "webPort", port));
+                        Integer.toString(SortedProperties.getIntProperty(old, "webPort", port)));
                 prop.setProperty("webAllowOthers",
-                        "" + SortedProperties.getBooleanProperty(old,
-                        "webAllowOthers", allowOthers));
+                        Boolean.toString(SortedProperties.getBooleanProperty(old, "webAllowOthers", allowOthers)));
                 prop.setProperty("webSSL",
-                        "" + SortedProperties.getBooleanProperty(old,
-                        "webSSL", ssl));
+                        Boolean.toString(SortedProperties.getBooleanProperty(old, "webSSL", ssl)));
                 if (commandHistoryString != null) {
                     prop.setProperty(COMMAND_HISTORY, commandHistoryString);
                 }

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

@@ -808,7 +808,7 @@ public class TableFilter implements ColumnResolver {
                 IndexLookupBatch lookupBatch = joinBatch.getLookupBatch(joinFilterId);
                 if (lookupBatch == null) {
                     if (joinFilterId != 0) {
-                        throw DbException.throwInternalError("" + joinFilterId);
+                        throw DbException.throwInternalError(Integer.toString(joinFilterId));
                     }
                 } else {
                     planBuff.append("batched:");

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

@@ -264,7 +264,7 @@ public class CompressTool {
         default:
             throw DbException.get(
                     ErrorCode.UNSUPPORTED_COMPRESSION_ALGORITHM_1,
-                    "" + algorithm);
+                    Integer.toString(algorithm));
         }
     }
 

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

@@ -65,7 +65,7 @@ public class MultiDimension implements Comparator<long[]> {
      */
     public int getMaxValue(int dimensions) {
         if (dimensions < 2 || dimensions > 32) {
-            throw new IllegalArgumentException("" + dimensions);
+            throw new IllegalArgumentException(Integer.toString(dimensions));
         }
         int bitsPerValue = getBitsPerValue(dimensions);
         return (int) ((1L << bitsPerValue) - 1);
@@ -270,18 +270,18 @@ public class MultiDimension implements Comparator<long[]> {
     private void addMortonRanges(ArrayList<long[]> list, int[] min, int[] max,
             int len, int level) {
         if (level > 100) {
-            throw new IllegalArgumentException("" + level);
+            throw new IllegalArgumentException(Integer.toString(level));
         }
         int largest = 0, largestDiff = 0;
         long size = 1;
         for (int i = 0; i < len; i++) {
             int diff = max[i] - min[i];
             if (diff < 0) {
-                throw new IllegalArgumentException(""+ diff);
+                throw new IllegalArgumentException(Integer.toString(diff));
             }
             size *= diff + 1;
             if (size < 0) {
-                throw new IllegalArgumentException("" + size);
+                throw new IllegalArgumentException(Long.toString(size));
             }
             if (diff > largestDiff) {
                 largestDiff = diff;

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

@@ -102,7 +102,8 @@ public class ColumnNamer {
         }
         // go with a innocuous default name pattern
         if (columnName == null) {
-            columnName = configuration.getDefaultColumnNamePattern().replace("$$", "" + (indexOfColumn + 1));
+            columnName = configuration.getDefaultColumnNamePattern()
+                    .replace("$$", Integer.toString(indexOfColumn + 1));
         }
         if (existingColumnNames.contains(columnName) && configuration.isGenerateUniqueColumnNames()) {
             columnName = generateUniqueName(columnName);

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

@@ -86,7 +86,7 @@ public abstract class LazyFuture<T> implements Future<T> {
         case S_CANCELED:
             throw new CancellationException();
         default:
-            throw DbException.throwInternalError("" + state);
+            throw DbException.throwInternalError(Integer.toString(state));
         }
     }
 

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

@@ -178,7 +178,7 @@ public class NetUtils {
             return new ServerSocket(port, 0, bindAddress);
         } catch (BindException be) {
             throw DbException.get(ErrorCode.EXCEPTION_OPENING_PORT_2,
-                    be, "" + port, be.toString());
+                    be, Integer.toString(port), be.toString());
         } catch (IOException e) {
             throw DbException.convertIOException(e, "port: " + port + " ssl: " + ssl);
         }

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

@@ -207,7 +207,7 @@ public class Profiler implements Runnable {
 
     private static List<Object[]> readRunnableStackTraces(int pid) {
         try {
-            String jstack = exec("jstack", "" + pid);
+            String jstack = exec("jstack", Integer.toString(pid));
             LineNumberReader r = new LineNumberReader(
                     new StringReader(jstack));
             return readStackTrace(r);

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

@@ -69,7 +69,7 @@ public class SortedProperties extends Properties {
      * @return the value if set, or the default value if not
      */
     public static int getIntProperty(Properties prop, String key, int def) {
-        String value = prop.getProperty(key, "" + def);
+        String value = prop.getProperty(key, Integer.toString(def));
         try {
             return Integer.decode(value);
         } catch (Exception e) {

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

@@ -948,7 +948,7 @@ public class DataType {
             return Value.RESULT_SET;
         default:
             throw DbException.get(
-                    ErrorCode.UNKNOWN_DATA_TYPE_1, "" + sqlType);
+                    ErrorCode.UNKNOWN_DATA_TYPE_1, Integer.toString(sqlType));
         }
     }
 

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

@@ -779,7 +779,7 @@ public abstract class Value {
                     double d = getDouble();
                     if (Double.isInfinite(d) || Double.isNaN(d)) {
                         throw DbException.get(
-                                ErrorCode.DATA_CONVERSION_ERROR_1, "" + d);
+                                ErrorCode.DATA_CONVERSION_ERROR_1, Double.toString(d));
                     }
                     return ValueDecimal.get(BigDecimal.valueOf(d));
                 }
@@ -787,7 +787,7 @@ public abstract class Value {
                     float f = getFloat();
                     if (Float.isInfinite(f) || Float.isNaN(f)) {
                         throw DbException.get(
-                                ErrorCode.DATA_CONVERSION_ERROR_1, "" + f);
+                                ErrorCode.DATA_CONVERSION_ERROR_1, Float.toString(f));
                     }
                     // better rounding behavior than BigDecimal.valueOf(f)
                     return ValueDecimal.get(new BigDecimal(Float.toString(f)));