Unnecessary since the queue object is thread local. poll() and offer() are likely more expensive than a simple ArrayDeque which is used in the ByteBufferProxy object pool implementation. Additionally, concurrent queue is fixed size meaning the offer() in DirectBufferProxy.deallocate() can fail abandoning the DirectBuffer to be garbage collected (though perhaps this is desired?) unlike the ArrayDeque used in ByteBufferProxy which resizes it's capacity when offer() is called while full.