diff --git a/jetty-io/src/main/java/org/eclipse/jetty/io/ArrayByteBufferPool.java b/jetty-io/src/main/java/org/eclipse/jetty/io/ArrayByteBufferPool.java
index bfb498ad124..8da443ebd9d 100644
--- a/jetty-io/src/main/java/org/eclipse/jetty/io/ArrayByteBufferPool.java
+++ b/jetty-io/src/main/java/org/eclipse/jetty/io/ArrayByteBufferPool.java
@@ -20,8 +20,6 @@ package org.eclipse.jetty.io;
 
 import java.nio.ByteBuffer;
 
-import org.eclipse.jetty.util.BufferUtil;
-
 public class ArrayByteBufferPool implements ByteBufferPool
 {
     private final int _min;
@@ -63,8 +61,8 @@ public class ArrayByteBufferPool implements ByteBufferPool
         for (int i=0;i<_direct.length;i++)
         {
             size+=_inc;
-            _direct[i]=new ByteBufferPool.Bucket(size,_maxQueue);
-            _indirect[i]=new ByteBufferPool.Bucket(size,_maxQueue);
+            _direct[i]=new ByteBufferPool.Bucket(this,size,_maxQueue);
+            _indirect[i]=new ByteBufferPool.Bucket(this,size,_maxQueue);
         }
     }
 
@@ -73,7 +71,7 @@ public class ArrayByteBufferPool implements ByteBufferPool
     {
         ByteBufferPool.Bucket bucket = bucketFor(size,direct);
         if (bucket==null)
-            return direct ? BufferUtil.allocateDirect(size) : BufferUtil.allocate(size);
+            return newByteBuffer(size,direct);
             
         return bucket.acquire(direct);
             
diff --git a/jetty-io/src/main/java/org/eclipse/jetty/io/ByteBufferPool.java b/jetty-io/src/main/java/org/eclipse/jetty/io/ByteBufferPool.java
index 4944dac91c5..4bb2afce13d 100644
--- a/jetty-io/src/main/java/org/eclipse/jetty/io/ByteBufferPool.java
+++ b/jetty-io/src/main/java/org/eclipse/jetty/io/ByteBufferPool.java
@@ -55,6 +55,11 @@ public interface ByteBufferPool
      * @see #acquire(int, boolean)
      */
     public void release(ByteBuffer buffer);
+    
+    default ByteBuffer newByteBuffer(int capacity, boolean direct)
+    {
+        return direct ? BufferUtil.allocateDirect(capacity) : BufferUtil.allocate(capacity);
+    }
 
     public static class Lease
     {
@@ -119,14 +124,17 @@ public interface ByteBufferPool
         }
     }
 
+    
     class Bucket
     {
+        private final ByteBufferPool _pool;
         private final int _capacity;
         private final AtomicInteger _space;
         private final Queue<ByteBuffer> _queue= new ConcurrentArrayQueue<>();
 
-        public Bucket(int bufferSize,int maxSize)
+        public Bucket(ByteBufferPool pool, int bufferSize,int maxSize)
         {
+            _pool=pool;
             _capacity=bufferSize;
             _space=maxSize>0?new AtomicInteger(maxSize):null;
         }
@@ -146,7 +154,7 @@ public interface ByteBufferPool
         {
             ByteBuffer buffer = _queue.poll();
             if (buffer == null) 
-               return direct ? BufferUtil.allocateDirect(_capacity) : BufferUtil.allocate(_capacity);
+               return _pool.newByteBuffer(_capacity,direct);
             if (_space!=null)
                 _space.incrementAndGet();
             return buffer;        
diff --git a/jetty-io/src/main/java/org/eclipse/jetty/io/MappedByteBufferPool.java b/jetty-io/src/main/java/org/eclipse/jetty/io/MappedByteBufferPool.java
index 335d6ccba7b..11af00c7273 100644
--- a/jetty-io/src/main/java/org/eclipse/jetty/io/MappedByteBufferPool.java
+++ b/jetty-io/src/main/java/org/eclipse/jetty/io/MappedByteBufferPool.java
@@ -22,6 +22,7 @@ import java.nio.ByteBuffer;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Function;
 
 import org.eclipse.jetty.util.BufferUtil;
 
@@ -31,6 +32,7 @@ public class MappedByteBufferPool implements ByteBufferPool
     private final ConcurrentMap<Integer, Bucket> heapBuffers = new ConcurrentHashMap<>();
     private final int _factor;
     private final int _maxQueue;
+    private final Function<Integer, Bucket> _newBucket;
 
     public MappedByteBufferPool()
     {
@@ -39,13 +41,19 @@ public class MappedByteBufferPool implements ByteBufferPool
 
     public MappedByteBufferPool(int factor)
     {
-        this(factor,-1);
+        this(factor,-1,null);
     }
     
     public MappedByteBufferPool(int factor,int maxQueue)
+    {
+        this(factor,maxQueue,null);
+    }
+    
+    public MappedByteBufferPool(int factor,int maxQueue,Function<Integer, Bucket> newBucket)
     {
         _factor = factor<=0?1024:factor;
-        _maxQueue=maxQueue;
+        _maxQueue = maxQueue;
+        _newBucket = newBucket!=null?newBucket:i->new Bucket(this,i*_factor,_maxQueue);
     }
 
     @Override
@@ -60,12 +68,6 @@ public class MappedByteBufferPool implements ByteBufferPool
         return bucket.acquire(direct);
     }
 
-    protected ByteBuffer newByteBuffer(int capacity, boolean direct)
-    {
-        return direct ? BufferUtil.allocateDirect(capacity)
-                      : BufferUtil.allocate(capacity);
-    }
-
     @Override
     public void release(ByteBuffer buffer)
     {
@@ -78,13 +80,15 @@ public class MappedByteBufferPool implements ByteBufferPool
         int b = bucketFor(buffer.capacity());
         ConcurrentMap<Integer, Bucket> buckets = bucketsFor(buffer.isDirect());
 
-        Bucket bucket = buckets.computeIfAbsent(b,bi->new Bucket(b*_factor,_maxQueue));
+        Bucket bucket = buckets.computeIfAbsent(b,_newBucket);
         bucket.release(buffer);
     }
 
     public void clear()
     {
+        directBuffers.values().forEach(Bucket::clear);
         directBuffers.clear();
+        heapBuffers.values().forEach(Bucket::clear);
         heapBuffers.clear();
     }
 
@@ -107,7 +111,7 @@ public class MappedByteBufferPool implements ByteBufferPool
         private final AtomicInteger tag = new AtomicInteger();
 
         @Override
-        protected ByteBuffer newByteBuffer(int capacity, boolean direct)
+        public ByteBuffer newByteBuffer(int capacity, boolean direct)
         {
             ByteBuffer buffer = super.newByteBuffer(capacity + 4, direct);
             buffer.limit(buffer.capacity());