How can we allocate a direct CharBuffer if we don't have any respective (allocateDirect) methods in `CharBuffer` or `Buffer`?

Question

Why do we have isDirect() method in CharBuffer?

How can we allocate a direct CharBuffer if we don't have any respective (allocateDirect) methods in CharBuffer or Buffer ?

I may guess it is:

ByteBuffer.alocateDirect(100).asCharBuffer()

Is this so and is it the only (and recommended) way to do it?

A char is not a byte in Java – m0skit0 Mar 31 '19 at 16:45 — m0skit0, Mar 31 '19 at 16:45
I added an explanation for the U/S/R suffixes. – LppEdd Mar 31 '19 at 17:12 — LppEdd, Mar 31 '19 at 17:12
Do you need other clarifications? – LppEdd Apr 03 '19 at 07:31 — LppEdd, Apr 03 '19 at 07:31

LppEdd · Answer 1 · 2019-03-31T17:12:05.793

CharBuffer inherits that method from the Buffer interface, with many others.
CharBuffer has multiple sub-classes

For example the DirectCharBuffer(s) return true.
This

ByteBuffer.allocateDirect(20).asCharBuffer();

will return a DirectCharBuffer, which is a CharBuffer.

*U suffix for big-endian systems.
*S suffix for other kinds (little-endian).
*R suffix for read-only buffers.

final CharBuffer cb = ByteBuffer.allocateDirect(20).asCharBuffer();
final boolean direct = cb.isDirect();  // true

Is this so and is it the only (~~and recommended~~) way to do it?

Yes.

For reference, what is a direct buffer? See JavaDoc, section Direct vs. non-direct buffers.

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