Make FindBugs happy

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

@@ -25,7 +25,7 @@ public class FileObjectMemory implements FileObject {
     private static final int BLOCK_SIZE_MASK = BLOCK_SIZE - 1;
     private static final CompressLZF LZF = new CompressLZF();
     private static final byte[] BUFFER = new byte[BLOCK_SIZE * 2];
-    private static byte[] cachedCompressedEmptyBlock;
+    private static final byte[] COMPRESSED_EMPTY_BLOCK;
 
 //## Java 1.4 begin ##
     private static final Cache<CompressItem, CompressItem> COMPRESS_LATER = new Cache<CompressItem, CompressItem>(CACHE_SIZE);
@@ -38,6 +38,13 @@ public class FileObjectMemory implements FileObject {
     private byte[][] data;
     private long lastModified;
 
+    static {
+        byte[] n = new byte[BLOCK_SIZE];
+        int len = LZF.compress(n, BLOCK_SIZE, BUFFER, 0);
+        COMPRESSED_EMPTY_BLOCK = new byte[len];
+        System.arraycopy(BUFFER, 0, COMPRESSED_EMPTY_BLOCK, 0, len);
+    }
+
     /**
      * This small cache compresses the data if an element leaves the cache.
      */
@@ -77,7 +84,7 @@ public class FileObjectMemory implements FileObject {
         int page;
 
         public int hashCode() {
-            return data.hashCode() ^ page;
+            return page;
         }
 
         public boolean equals(Object o) {
@@ -138,16 +145,6 @@ public class FileObjectMemory implements FileObject {
         }
     }
 
-    static byte[] getCompressedEmptyBlock() {
-        if (cachedCompressedEmptyBlock == null) {
-            byte[] n = new byte[BLOCK_SIZE];
-            int len = LZF.compress(n, BLOCK_SIZE, BUFFER, 0);
-            cachedCompressedEmptyBlock = new byte[len];
-            System.arraycopy(BUFFER, 0, cachedCompressedEmptyBlock, 0, len);
-        }
-        return cachedCompressedEmptyBlock;
-    }
-
     private void touch() {
         lastModified = System.currentTimeMillis();
     }
@@ -190,7 +187,7 @@ public class FileObjectMemory implements FileObject {
             byte[][] n = new byte[blocks][];
             System.arraycopy(data, 0, n, 0, Math.min(data.length, n.length));
             for (int i = data.length; i < blocks; i++) {
-                n[i] = getCompressedEmptyBlock();
+                n[i] = COMPRESSED_EMPTY_BLOCK;
             }
             data = n;
         }

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

@@ -167,7 +167,7 @@ public class FileSystemDisk extends FileSystem {
             dir = null;
         } else {
             dir = new File(name).getAbsoluteFile().getParentFile();
-            dir.mkdirs();
+            FileUtils.mkdirs(dir);
         }
         if (prefix.length() < 3) {
             prefix += "0";
@@ -304,7 +304,7 @@ public class FileSystemDisk extends FileSystem {
             }
             File dir = new File(parent);
             for (int i = 0; i < SysProperties.MAX_FILE_RETRY; i++) {
-                if (dir.exists() || dir.mkdirs()) {
+                if ((dir.exists() && dir.isDirectory()) || dir.mkdirs()) {
                     return;
                 }
                 wait(i);

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

@@ -27,6 +27,29 @@ public class FileUtils {
         // utility class
     }
 
+    /**
+     * Create the directory and all parent directories if required.
+     *
+     * @param directory the directory
+     * @throws IOException
+     */
+    public static void mkdirs(File directory) throws IOException {
+        // loop, to deal with race conditions (if another thread creates or
+        // deletes the same directory at the same time).
+        for (int i = 0; i < 5; i++) {
+            if (directory.exists()) {
+                if (directory.isDirectory()) {
+                    return;
+                }
+                throw new IOException("Could not create directory, because a file with the same name already exists: " + directory.getAbsolutePath());
+            }
+            if (directory.mkdirs()) {
+                return;
+            }
+        }
+        throw new IOException("Could not create directory: " + directory.getAbsolutePath());
+    }
+
     /**
      * Change the length of the file.
      *

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

@@ -60,7 +60,7 @@ public class CompareMode {
      * @param strength the collation strength
      * @return the compare mode
      */
-    public static CompareMode getInstance(String name, int strength) {
+    public static synchronized CompareMode getInstance(String name, int strength) {
         if (lastUsed != null) {
             if (StringUtils.equals(lastUsed.name, name)) {
                 if (lastUsed.strength == strength) {