What is the difference(s) between ByteBuffer modes?

Question

I just interested about the difference between these two guys ByteBuffer.allocateDirect(4) and ByteBuffer.allocate(4)

and why when I call the array() method of direct one, it throws exception? what is the difference? would you provide a simple example and usage too? many thanks.

http://stackoverflow.com/questions/5670862/bytebuffer-allocate-vs-bytebuffer-allocatedirect — Jean Logeart, Dec 05 '13 at 12:46

score 0 · Answer 1 · answered Dec 05 '13 at 12:52

When I call the array() method of direct one, it throws exception? What is the difference?

A HeapByteBuffer (from allocate()), is backed by an array, but a DirectByteBuffer (from allocateDirect()) is backed by an block of unmanaged memory, which it accesses directly. It has no backing array, and thus calling array() will throw.

The question @Vakh links to in his comment explains the differences nicely.

What is the difference(s) between ByteBuffer modes?

1 Answers1