MVStore: unified exception handling; the version is included in the messages.…

MVStore: unified exception handling; the version is included in the messages. Old data is now retained for 45 seconds by default.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,9 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>MVStore: compress is now disabled by default, and can be enabled on request.
+<ul><li>MVStore: unified exception handling; the version is included in the messages.
+</li><li>MVStore: old data is now retained for 45 seconds by default.
+</ul><li>MVStore: compress is now disabled by default, and can be enabled on request.
 </li></ul>
 
 <h2>Version 1.3.170 (2012-11-30)</h2>

h2/src/docsrc/html/features.html

@@ -138,7 +138,7 @@ encrypted using AES-128 and XTEA encryption algorithms
 
 <h3>Other Features and Tools</h3>
 <ul>
-<li>Small footprint (smaller than 1 MB), low memory requirements
+<li>Small footprint (smaller than 1.5 MB), low memory requirements
 </li><li>Multiple index types (b-tree, tree, hash)
 </li><li>Support for multi-dimensional indexes
 </li><li>CSV (comma separated values) file support
@@ -350,9 +350,9 @@ H2 1.3,
 <td class="compareY">Yes</td>
 </tr><tr>
 <td>Footprint (jar/dll size)</td>
-<td>~1 MB *5</td>
-<td>~2 MB</td>
-<td>~1 MB</td>
+<td>~1.5 MB *5</td>
+<td>~3 MB</td>
+<td>~1.5 MB</td>
 <td>~4 MB</td>
 <td>~6 MB</td>
 </tr>

h2/src/docsrc/html/mainWeb.html

@@ -27,7 +27,7 @@ Welcome to H2, the Java SQL database. The main features of H2 are:
 <li>Very fast, open source, JDBC API
 </li><li>Embedded and server modes; in-memory databases
 </li><li>Browser based Console application
-</li><li>Small footprint: around 1 MB jar file size
+</li><li>Small footprint: around 1.5 MB jar file size
 </li></ul>
 
 <table style="border: 0px; width: 470px;">

h2/src/docsrc/html/mvstore.html

@@ -327,6 +327,22 @@ with a fluent API to simplify building a store instance.
 There is a tool (<code>MVStoreTool</code>) to dump the contents of a file.
 </p>
 
+<h3>Exception Handling</h3>
+<p>
+This tool does not throw checked exceptions. 
+Instead, unchecked exceptions are thrown if needed. 
+The error message always contains the version of the tool.
+The following exceptions can occur:
+</p>
+<ul><li><code>IllegalStateException</code> if a map was already closed, 
+    in IO exception occurred, for example if the file was locked, is already closed, 
+    could not be opened or closed, if reading or writing failed, 
+    if the file is corrupt, or if there is an internal error in the tool. 
+</li><li><code>IllegalArgumentException</code> if a method was called with an illegal argument.
+</li><li><code>UnsupportedOperationException</code> if a method was called that is not supported,
+    for example trying to modify a read-only map or view.
+</ul>
+
 <h2 id="differences">Similar Projects and Differences to Other Storage Engines</h2>
 <p>
 Unlike similar storage engines like LevelDB and Kyoto Cabinet, the MVStore is written in Java

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

@@ -53,7 +53,7 @@ public class ChangeCursor<K, V> implements Iterator<K> {
     }
 
     public void remove() {
-        throw new UnsupportedOperationException();
+        throw DataUtils.unsupportedOperationException("Removing is not supported");
     }
 
     private void fetchNext() {

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

@@ -89,7 +89,7 @@ public class Chunk {
      */
     static Chunk fromHeader(ByteBuffer buff, long start) {
         if (buff.get() != 'c') {
-            throw new RuntimeException("File corrupt");
+            throw DataUtils.illegalStateException("File corrupt reading chunk at position " + start);
         }
         int length = buff.getInt();
         int chunkId = buff.getInt();

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

@@ -67,7 +67,7 @@ public class Cursor<K> implements Iterator<K> {
     }
 
     public void remove() {
-        throw new UnsupportedOperationException();
+        throw DataUtils.unsupportedOperationException("Removing is not supported");
     }
 
     /**

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

@@ -14,6 +14,7 @@ import java.nio.channels.FileChannel;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import org.h2.engine.Constants;
 import org.h2.util.New;
 
 /**
@@ -304,7 +305,8 @@ public class DataUtils {
      * @param pos the absolute position within the file
      * @param dst the byte buffer
      */
-    public static void readFully(FileChannel file, long pos, ByteBuffer dst) throws IOException {
+    public static void readFully(FileChannel file, long pos, ByteBuffer dst) {
+        try {
             do {
                 int len = file.read(dst, pos);
                 if (len < 0) {
@@ -313,6 +315,9 @@ public class DataUtils {
                 pos += len;
             } while (dst.remaining() > 0);
             dst.rewind();
+        } catch (IOException e) {
+            throw illegalStateException("Reading from " + file + "  failed; length " + dst.remaining() + " at " + pos, e);
+        }
     }
 
     /**
@@ -322,12 +327,16 @@ public class DataUtils {
      * @param pos the absolute position within the file
      * @param src the source buffer
      */
-    public static void writeFully(FileChannel file, long pos, ByteBuffer src) throws IOException {
+    public static void writeFully(FileChannel file, long pos, ByteBuffer src) {
+        try {
             int off = 0;
             do {
                 int len = file.write(src, pos + off);
                 off += len;
             } while (src.remaining() > 0);
+        } catch (IOException e) {
+            throw illegalStateException("Writing to " + file + "  failed; length " + src.remaining() + " at " + pos, e);
+        }
     }
 
 
@@ -544,4 +553,25 @@ public class DataUtils {
         return (s2 << 16) | s1;
     }
 
+    public static IllegalStateException illegalStateException(String message) {
+        return new IllegalStateException(message + version());
+    }
+
+    public static IllegalStateException illegalStateException(String message, Exception e) {
+        return new IllegalStateException(message + version(), e);
+    }
+
+    public static IllegalArgumentException illegalArgumentException(String message) {
+        return new IllegalArgumentException(message + version());
+    }
+
+    public static UnsupportedOperationException unsupportedOperationException(String message) {
+        return new UnsupportedOperationException(message + version());
+    }
+
+    private static String version() {
+        return " [" + Constants.VERSION_MAJOR + "." +
+                Constants.VERSION_MINOR + "." + Constants.BUILD_ID + "]";
+    }
+
 }

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

@@ -839,7 +839,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      */
     protected void checkOpen() {
         if (closed) {
-            throw new IllegalStateException("This map is closed");
+            throw DataUtils.illegalStateException("This map is closed");
         }
     }
 
@@ -851,7 +851,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
     protected void checkWrite() {
         if (readOnly) {
             checkOpen();
-            throw new IllegalStateException("This map is read-only");
+            throw DataUtils.unsupportedOperationException("This map is read-only");
         }
     }
 
@@ -893,10 +893,11 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      */
     public MVMap<K, V> openVersion(long version) {
         if (readOnly) {
-            throw new IllegalArgumentException("This map is read-only - need to call the method on the writable map");
+            throw DataUtils.unsupportedOperationException(
+                    "This map is read-only - need to call the method on the writable map");
         }
         if (version < createVersion) {
-            throw new IllegalArgumentException("Unknown version");
+            throw DataUtils.illegalArgumentException("Unknown version");
         }
         Page newest = null;
         // need to copy because it can change

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

@@ -28,6 +28,7 @@ import org.h2.mvstore.type.StringDataType;
 import org.h2.store.fs.FilePath;
 import org.h2.store.fs.FileUtils;
 import org.h2.util.New;
+import org.h2.util.StringUtils;
 
 /*
 
@@ -40,8 +41,6 @@ header:
 H:3,...
 
 TODO:
-- allocate memory with Utils.newBytes and so on
-- unified exception handling
 - concurrent map; avoid locking during IO (pre-load pages)
 - maybe split database into multiple files, to speed up compact
 - automated 'kill process' and 'power failure' test
@@ -90,6 +89,8 @@ TODO:
 - auto-save if there are too many changes (required for StreamStore)
 - StreamStore optimization: avoid copying bytes
 - unlimited transaction size
+- MVStoreTool.shrink to shrink a store (create, copy, rename, delete)
+-- and for MVStore on Windows, auto-detect renamed file
 
 */
 
@@ -320,7 +321,7 @@ public class MVStore {
     private MVMap<String, String> getMetaMap(long version) {
         Chunk c = getChunkForVersion(version);
         if (c == null) {
-            throw new IllegalArgumentException("Unknown version: " + version);
+            throw DataUtils.illegalArgumentException("Unknown version: " + version);
         }
         c = readChunkHeader(c.start);
         MVMap<String, String> oldMeta = meta.openReadOnly();
@@ -353,10 +354,6 @@ public class MVStore {
         if (clazz == String.class) {
             return StringDataType.INSTANCE;
         }
-        if (dataTypeFactory == null) {
-            throw new RuntimeException("No data type factory set " +
-                    "and don't know how to serialize " + clazz);
-        }
         String s = dataTypeFactory.getDataType(clazz);
         return dataTypeFactory.buildDataType(s);
     }
@@ -390,12 +387,12 @@ public class MVStore {
             if (readOnly) {
                 fileLock = file.tryLock(0, Long.MAX_VALUE, true);
                 if (fileLock == null) {
-                    throw new RuntimeException("The file is locked: " + fileName);
+                    throw new IOException("The file is locked: " + fileName);
                 }
             } else {
                 fileLock = file.tryLock();
                 if (fileLock == null) {
-                    throw new RuntimeException("The file is locked: " + fileName);
+                    throw new IOException("The file is locked: " + fileName);
                 }
             }
             fileSize = file.size();
@@ -414,8 +411,12 @@ public class MVStore {
                 }
             }
         } catch (Exception e) {
+            try {
                 close();
-            throw convert(e);
+            } catch (Exception e2) {
+                // ignore
+            }
+            throw DataUtils.illegalStateException("Could not open " + fileName, e);
         }
     }
 
@@ -445,12 +446,11 @@ public class MVStore {
     }
 
     private void readFileHeader() {
-        try {
         byte[] headers = new byte[2 * BLOCK_SIZE];
         fileReadCount++;
         DataUtils.readFully(file, 0, ByteBuffer.wrap(headers));
         for (int i = 0; i <= BLOCK_SIZE; i += BLOCK_SIZE) {
-                String s = new String(headers, i, BLOCK_SIZE, "UTF-8").trim();
+            String s = StringUtils.utf8Decode(headers, i, BLOCK_SIZE).trim();
             fileHeader = DataUtils.parseMap(s);
             rootChunkStart = Long.parseLong(fileHeader.get("rootChunk"));
             creationTime = Long.parseLong(fileHeader.get("creationTime"));
@@ -458,32 +458,28 @@ public class MVStore {
             lastMapId = Integer.parseInt(fileHeader.get("lastMapId"));
             int check = (int) Long.parseLong(fileHeader.get("fletcher"), 16);
             s = s.substring(0, s.lastIndexOf("fletcher") - 1) + " ";
-                byte[] bytes = s.getBytes("UTF-8");
+            byte[] bytes = StringUtils.utf8Encode(s);
             int checksum = DataUtils.getFletcher32(bytes,
                     bytes.length / 2 * 2);
             if (check == checksum) {
                 return;
             }
         }
-            throw new RuntimeException("File header is corrupt");
-        } catch (Exception e) {
-            throw convert(e);
-        }
+        throw DataUtils.illegalStateException("File header is corrupt");
     }
 
     private void writeFileHeader() {
-        try {
         StringBuilder buff = new StringBuilder();
         fileHeader.put("lastMapId", "" + lastMapId);
         fileHeader.put("rootChunk", "" + rootChunkStart);
         fileHeader.put("version", "" + currentVersion);
         DataUtils.appendMap(buff, fileHeader);
-            byte[] bytes = (buff.toString() + " ").getBytes("UTF-8");
+        byte[] bytes = StringUtils.utf8Encode(buff.toString() + " ");
         int checksum = DataUtils.getFletcher32(bytes, bytes.length / 2 * 2);
         DataUtils.appendMap(buff, "fletcher", Integer.toHexString(checksum));
-            bytes = buff.toString().getBytes("UTF-8");
+        bytes = StringUtils.utf8Encode(buff.toString());
         if (bytes.length > BLOCK_SIZE) {
-                throw new IllegalArgumentException("File header too large: " + buff);
+            throw DataUtils.illegalArgumentException("File header too large: " + buff);
         }
         ByteBuffer header = ByteBuffer.allocate(2 * BLOCK_SIZE);
         header.put(bytes);
@@ -493,13 +489,6 @@ public class MVStore {
         fileWriteCount++;
         DataUtils.writeFully(file,  0, header);
         fileSize = Math.max(fileSize, 2 * BLOCK_SIZE);
-        } catch (Exception e) {
-            throw convert(e);
-        }
-    }
-
-    private static RuntimeException convert(Exception e) {
-        throw new RuntimeException("Exception: " + e, e);
     }
 
     /**
@@ -524,7 +513,7 @@ public class MVStore {
                 maps.clear();
                 mapsChanged.clear();
             } catch (Exception e) {
-                throw convert(e);
+                throw DataUtils.illegalStateException("Closing failed for file " + fileName, e);
             } finally {
                 file = null;
             }
@@ -645,7 +634,7 @@ public class MVStore {
 
         if (ASSERT) {
             if (freedChunks.size() > 0) {
-                throw new RuntimeException("Temporary freed chunks");
+                throw DataUtils.illegalStateException("Temporary freed chunks");
             }
         }
 
@@ -672,12 +661,8 @@ public class MVStore {
         c.metaRootPos = meta.getRoot().getPos();
         c.writeHeader(buff);
         buff.rewind();
-        try {
         fileWriteCount++;
         DataUtils.writeFully(file, filePos, buff);
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
         fileSize = Math.max(fileSize, filePos + buff.position());
         rootChunkStart = filePos;
         revertTemp();
@@ -704,7 +689,7 @@ public class MVStore {
                 Chunk c = chunks.get(f.id);
                 c.maxLengthLive += f.maxLengthLive;
                 if (c.maxLengthLive < 0) {
-                    throw new RuntimeException("Corrupt max length");
+                    throw DataUtils.illegalStateException("Corrupt max length: " + c.maxLengthLive);
                 }
             }
         }
@@ -719,7 +704,6 @@ public class MVStore {
      */
     private void shrinkFileIfPossible(int minPercent) {
         long used = getFileLengthUsed();
-        try {
         if (used >= fileSize) {
             return;
         }
@@ -730,11 +714,12 @@ public class MVStore {
         if (savedPercent < minPercent) {
             return;
         }
+        try {
             file.truncate(used);
-            fileSize = used;
-        } catch (Exception e) {
-            throw convert(e);
+        } catch (IOException e) {
+            throw DataUtils.illegalStateException("Could not truncate to size " + used, e);
         }
+        fileSize = used;
     }
 
     private long getFileLengthUsed() {
@@ -800,15 +785,11 @@ public class MVStore {
     }
 
     private Chunk readChunkHeader(long start) {
-        try {
         fileReadCount++;
         ByteBuffer buff = ByteBuffer.allocate(40);
         DataUtils.readFully(file, start, buff);
         buff.rewind();
         return Chunk.fromHeader(buff, start);
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
     }
 
     /**
@@ -898,11 +879,7 @@ public class MVStore {
 
     private void copyLive(Chunk chunk, ArrayList<Chunk> old) {
         ByteBuffer buff = ByteBuffer.allocate(chunk.length);
-        try {
         DataUtils.readFully(file, chunk.start, buff);
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
         Chunk.fromHeader(buff, chunk.start);
         int chunkLength = chunk.length;
         // mark a change, even if it doesn't look like there was a change
@@ -967,7 +944,7 @@ public class MVStore {
         if (p == null) {
             Chunk c = getChunk(pos);
             if (c == null) {
-                throw new RuntimeException("Chunk " + DataUtils.getPageChunkId(pos) + " not found");
+                throw DataUtils.illegalStateException("Chunk " + DataUtils.getPageChunkId(pos) + " not found");
             }
             long filePos = c.start;
             filePos += DataUtils.getPageOffset(pos);
@@ -1193,7 +1170,7 @@ public class MVStore {
      */
     public void rollbackTo(long version) {
         if (!isKnownVersion(version)) {
-            throw new IllegalArgumentException("Unknown version: " + version);
+            throw DataUtils.illegalArgumentException("Unknown version: " + version);
         }
         // TODO could remove newer temporary pages on rollback
         for (MVMap<?, ?> m : mapsChanged.values()) {

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

@@ -39,7 +39,7 @@ public class MVStoreBuilder {
 
     private MVStoreBuilder set(String key, Object value) {
         if (config.containsKey(key)) {
-            throw new IllegalArgumentException("Parameter " + config.get(key) + " is already set");
+            throw DataUtils.illegalArgumentException("Parameter " + config.get(key) + " is already set");
         }
         config.put(key, value);
         return this;

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

@@ -6,12 +6,12 @@
  */
 package org.h2.mvstore;
 
-import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.util.Arrays;
 import org.h2.compress.Compressor;
 import org.h2.mvstore.type.DataType;
+import org.h2.util.Utils;
 
 /**
  * A page (a node or a leaf).
@@ -129,7 +129,6 @@ public class Page {
             long pos, long filePos, long fileSize) {
         ByteBuffer buff;
         int maxLength = DataUtils.getPageMaxLength(pos);
-        try {
         maxLength = (int) Math.min(fileSize - filePos, maxLength);
         int length = maxLength;
         if (maxLength == Integer.MAX_VALUE) {
@@ -140,9 +139,6 @@ public class Page {
         }
         buff = ByteBuffer.allocate(length);
         DataUtils.readFully(file, filePos, buff);
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
         Page p = new Page(map, 0);
         p.pos = pos;
         int chunkId = DataUtils.getPageChunkId(pos);
@@ -409,7 +405,7 @@ public class Page {
                 }
             }
             if (check != totalCount) {
-                throw new AssertionError("Expected: " + check + " got: "
+                throw DataUtils.illegalStateException("Expected: " + check + " got: "
                         + totalCount);
             }
         }
@@ -653,20 +649,20 @@ public class Page {
         int start = buff.position();
         int pageLength = buff.getInt();
         if (pageLength > maxLength) {
-            throw new RuntimeException("Length too large, expected =< "
+            throw DataUtils.illegalStateException("File corrupted, expected length =< "
                     + maxLength + " got " + pageLength);
         }
         short check = buff.getShort();
         int mapId = DataUtils.readVarInt(buff);
         if (mapId != map.getId()) {
-            throw new RuntimeException("Error reading page, expected map "
+            throw DataUtils.illegalStateException("File corrupted, expected map id "
                     + map.getId() + " got " + mapId);
         }
         int checkTest = DataUtils.getCheckValue(chunkId)
                 ^ DataUtils.getCheckValue(offset)
                 ^ DataUtils.getCheckValue(pageLength);
         if (check != (short) checkTest) {
-            throw new RuntimeException("Error in check value, expected "
+            throw DataUtils.illegalStateException("File corrupted, expected check value "
                     + checkTest + " got " + check);
         }
         int len = DataUtils.readVarInt(buff);
@@ -679,7 +675,7 @@ public class Page {
             Compressor compressor = map.getStore().getCompressor();
             int lenAdd = DataUtils.readVarInt(buff);
             int compLen = pageLength + start - buff.position();
-            byte[] comp = new byte[compLen];
+            byte[] comp = Utils.newBytes(compLen);
             buff.get(comp);
             int l = compLen + lenAdd;
             buff = ByteBuffer.allocate(l);
@@ -865,7 +861,7 @@ public class Page {
     public int getMemory() {
         if (MVStore.ASSERT) {
             if (memory != calculateMemory()) {
-                throw new RuntimeException("Memory calculation error");
+                throw DataUtils.illegalStateException("Memory calculation error");
             }
         }
         return memory;

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

@@ -14,6 +14,7 @@ import java.nio.ByteBuffer;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicLong;
 import org.h2.util.IOUtils;
+import org.h2.util.StringUtils;
 
 /**
  * A facility to store streams in a map. Streams are split into blocks, which
@@ -207,7 +208,7 @@ public class StreamStore {
                 map.remove(k2);
                 break;
             default:
-                throw new IllegalArgumentException("Unsupported id");
+                throw DataUtils.illegalArgumentException("Unsupported id " + StringUtils.convertBytesToHex(id));
             }
         }
     }
@@ -238,7 +239,7 @@ public class StreamStore {
                 DataUtils.readVarLong(idBuffer);
                 break;
             default:
-                throw new IllegalArgumentException("Unsupported id");
+                throw DataUtils.illegalArgumentException("Unsupported id " + StringUtils.convertBytesToHex(id));
             }
         }
         return length;
@@ -401,7 +402,8 @@ public class StreamStore {
                     return nextBuffer();
                 }
                 default:
-                    throw new IllegalArgumentException("Unsupported id");
+                    throw DataUtils.illegalArgumentException("Unsupported id " +
+                            StringUtils.convertBytesToHex(idBuffer.array()));
                 }
             }
             return null;

h2/src/main/org/h2/mvstore/cache/CacheLongKeyLIRS.java

@@ -12,6 +12,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import org.h2.mvstore.DataUtils;
 
 /**
  * A scan resistant cache that uses keys of type long. It is meant to cache
@@ -65,7 +66,7 @@ public class CacheLongKeyLIRS<V> {
         setMaxMemory(maxMemory);
         setAverageMemory(averageMemory);
         if (Integer.bitCount(segmentCount) != 1) {
-            throw new IllegalArgumentException("The segment count must be a power of 2, is " + segmentCount);
+            throw DataUtils.illegalArgumentException("The segment count must be a power of 2, is " + segmentCount);
         }
         this.segmentCount = segmentCount;
         this.segmentMask = segmentCount - 1;
@@ -221,7 +222,7 @@ public class CacheLongKeyLIRS<V> {
      */
     public void setMaxMemory(long maxMemory) {
         if (maxMemory <= 0) {
-            throw new IllegalArgumentException("Max memory must be larger than 0");
+            throw DataUtils.illegalArgumentException("Max memory must be larger than 0");
         }
         this.maxMemory = maxMemory;
         if (segments != null) {
@@ -240,7 +241,7 @@ public class CacheLongKeyLIRS<V> {
      */
     public void setAverageMemory(int averageMemory) {
         if (averageMemory <= 0) {
-            throw new IllegalArgumentException("Average memory must be larger than 0");
+            throw DataUtils.illegalArgumentException("Average memory must be larger than 0");
         }
         this.averageMemory = averageMemory;
         if (segments != null) {
@@ -682,7 +683,7 @@ public class CacheLongKeyLIRS<V> {
          */
         synchronized V put(long key, int hash, V value, int memory) {
             if (value == null) {
-                throw new NullPointerException();
+                throw DataUtils.illegalArgumentException("The value may not be null");
             }
             V old;
             Entry<V> e = find(key, hash);
@@ -947,7 +948,7 @@ public class CacheLongKeyLIRS<V> {
          */
         void setMaxMemory(long maxMemory) {
             if (maxMemory <= 0) {
-                throw new IllegalArgumentException("Max memory must be larger than 0");
+                throw DataUtils.illegalArgumentException("Max memory must be larger than 0");
             }
             this.maxMemory = maxMemory;
         }
@@ -960,7 +961,7 @@ public class CacheLongKeyLIRS<V> {
          */
         void setAverageMemory(int averageMemory) {
             if (averageMemory <= 0) {
-                throw new IllegalArgumentException("Average memory must be larger than 0");
+                throw DataUtils.illegalArgumentException("Average memory must be larger than 0");
             }
             this.averageMemory = averageMemory;
         }

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

@@ -22,7 +22,7 @@ public class SpatialDataType implements DataType {
 
     public SpatialDataType(int dimensions) {
         if (dimensions <= 0 || dimensions > 255) {
-            throw new IllegalArgumentException("Dimensions: " + dimensions);
+            throw DataUtils.illegalArgumentException("Dimensions: " + dimensions);
         }
         this.dimensions = dimensions;
     }

h2/src/main/org/h2/mvstore/type/ObjectDataType.java

@@ -143,7 +143,7 @@ public class ObjectDataType implements DataType {
         case TYPE_SERIALIZED_OBJECT:
             return new SerializedObjectType(this);
         }
-        throw new RuntimeException("Unsupported type: " + typeId);
+        throw DataUtils.illegalStateException("Unsupported type: " + typeId);
     }
 
     @Override
@@ -196,7 +196,7 @@ public class ObjectDataType implements DataType {
                 } else if (tag >= TAG_BYTE_ARRAY_0_15 && tag <= TAG_BYTE_ARRAY_0_15 + 15) {
                     typeId = TYPE_BYTE_ARRAY;
                 } else {
-                    throw new RuntimeException("Unknown tag: " + tag);
+                    throw DataUtils.illegalStateException("Unknown tag: " + tag);
                 }
             }
         }
@@ -250,7 +250,7 @@ public class ObjectDataType implements DataType {
             return TYPE_CHARACTER;
         }
         if (obj == null) {
-            throw new NullPointerException();
+            throw DataUtils.illegalArgumentException("Null is not supported");
         }
         return TYPE_SERIALIZED_OBJECT;
     }
@@ -377,7 +377,7 @@ public class ObjectDataType implements DataType {
 
         @Override
         public final Object read(ByteBuffer buff) {
-            throw new RuntimeException();
+            throw DataUtils.illegalStateException("Internal error");
         }
 
         /**
@@ -1232,13 +1232,14 @@ public class ObjectDataType implements DataType {
 
         @Override
         public Object read(ByteBuffer buff, int tag) {
-            int len;
+            byte[] data;
             if (tag == TYPE_BYTE_ARRAY) {
-                len = DataUtils.readVarInt(buff);
+                int len = DataUtils.readVarInt(buff);
+                data = Utils.newBytes(len);
             } else {
-                len = tag - TAG_BYTE_ARRAY_0_15;
+                int len = tag - TAG_BYTE_ARRAY_0_15;
+                data = Utils.newBytes(len);
             }
-            byte[] data = new byte[len];
             buff.get(data);
             return data;
         }
@@ -1497,7 +1498,7 @@ public class ObjectDataType implements DataType {
         @Override
         public Object read(ByteBuffer buff, int tag) {
             int len = DataUtils.readVarInt(buff);
-            byte[] data = new byte[len];
+            byte[] data = Utils.newBytes(len);
             buff.get(data);
             return Utils.deserialize(data);
         }

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

@@ -365,7 +365,7 @@ public class StringUtils {
      * @param length the number of bytes
      * @return the text
      */
-    private static String utf8Decode(byte[] bytes, int offset, int length) {
+    public static String utf8Decode(byte[] bytes, int offset, int length) {
         try {
             return new String(bytes, offset, length, Constants.UTF8);
         } catch (Exception e) {

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

@@ -382,16 +382,20 @@ public class Utils {
      * Create an array of bytes with the given size. If this is not possible
      * because not enough memory is available, an OutOfMemoryError with the
      * requested size in the message is thrown.
+     * <p>
+     * This method should be used if the size of the array is user defined, or
+     * stored in a file, so wrong size data can be distinguished from regular
+     * out-of-memory.
      *
      * @param len the number of bytes requested
      * @return the byte array
      * @throws OutOfMemoryError
      */
     public static byte[] newBytes(int len) {
-        try {
         if (len == 0) {
             return EMPTY_BYTES;
         }
+        try {
             return new byte[len];
         } catch (OutOfMemoryError e) {
             Error e2 = new OutOfMemoryError("Requested memory: " + len);

h2/src/test/org/h2/test/store/TestCacheLIRS.java

@@ -10,7 +10,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Map.Entry;
 import java.util.Random;
-import org.h2.mvstore.cache.CacheLIRS;
+import org.h2.dev.cache.CacheLIRS;
 import org.h2.test.TestBase;
 import org.h2.util.New;
 

h2/src/test/org/h2/test/store/TestMVStore.java

@@ -130,14 +130,14 @@ public class TestMVStore extends TestBase {
             MVStore s1 = MVStoreBuilder.fileBased(fileName).open();
             s1.close();
             fail();
-        } catch (Exception e) {
+        } catch (IllegalStateException e) {
             // expected
         }
         try {
             MVStore s1 = MVStoreBuilder.fileBased(fileName).readOnly().open();
             s1.close();
             fail();
-        } catch (Exception e) {
+        } catch (IllegalStateException e) {
             // expected
         }
         s.close();

h2/src/main/org/h2/mvstore/cache/CacheLIRS.java → h2/src/tools/org/h2/dev/cache/CacheLIRS.java

@@ -4,7 +4,7 @@
  * (http://h2database.com/html/license.html).
  * Initial Developer: H2 Group
  */
-package org.h2.mvstore.cache;
+package org.h2.dev.cache;
 
 import java.util.AbstractMap;
 import java.util.ArrayList;
@@ -622,7 +622,7 @@ public class CacheLIRS<K, V> extends AbstractMap<K, V> implements Map<K, V> {
          */
         synchronized V put(K key, int hash, V value, int memory) {
             if (value == null) {
-                throw new NullPointerException();
+                throw new NullPointerException("The value may not be null");
             }
             V old;
             Entry<K, V> e = find(key, hash);