Index: lucene/CHANGES.txt
===================================================================
--- lucene/CHANGES.txt	(revision 1037654)
+++ lucene/CHANGES.txt	(working copy)
@@ -221,6 +221,9 @@
 * LUCENE-2699: Update StandardTokenizer and UAX29Tokenizer to Unicode 6.0.0.
   (Steven Rowe)
    
+* LUCENE-2778: RAMDirectory now exposes newRAMFile() which allows to override
+  and return a different RAMFile implementation. (Shai Erera)
+  
 Bug fixes
 
 * LUCENE-2216: OpenBitSet.hashCode returned different hash codes for
Index: lucene/src/java/org/apache/lucene/store/RAMDirectory.java
===================================================================
--- lucene/src/java/org/apache/lucene/store/RAMDirectory.java	(revision 1037654)
+++ lucene/src/java/org/apache/lucene/store/RAMDirectory.java	(working copy)
@@ -36,8 +36,8 @@
 
   private static final long serialVersionUID = 1l;
 
-  HashMap<String,RAMFile> fileMap = new HashMap<String,RAMFile>();
-  final AtomicLong sizeInBytes = new AtomicLong();
+  protected HashMap<String,RAMFile> fileMap = new HashMap<String,RAMFile>();
+  protected final AtomicLong sizeInBytes = new AtomicLong();
   
   // *****
   // Lock acquisition sequence:  RAMDirectory, then RAMFile
@@ -174,9 +174,8 @@
   @Override
   public synchronized void deleteFile(String name) throws IOException {
     ensureOpen();
-    RAMFile file = fileMap.get(name);
+    RAMFile file = fileMap.remove(name);
     if (file!=null) {
-        fileMap.remove(name);
         file.directory = null;
         sizeInBytes.addAndGet(-file.sizeInBytes);
     } else
@@ -187,7 +186,7 @@
   @Override
   public IndexOutput createOutput(String name) throws IOException {
     ensureOpen();
-    RAMFile file = new RAMFile(this);
+    RAMFile file = newRAMFile();
     synchronized (this) {
       RAMFile existing = fileMap.get(name);
       if (existing!=null) {
@@ -199,6 +198,15 @@
     return new RAMOutputStream(file);
   }
 
+  /**
+   * Returns a new {@link RAMFile} for storing data. This method can be
+   * overridden to return different {@link RAMFile} impls, that e.g. override
+   * {@link RAMFile#newBuffer(int)}.
+   */
+  protected RAMFile newRAMFile() {
+    return new RAMFile(this);
+  }
+
   /** Returns a stream reading an existing file. */
   @Override
   public IndexInput openInput(String name) throws IOException {