RFR: 8357847: (ch) WindowsAsynchronousFileChannelImpl should support FFM Buffers

[Brian Burkhalter]

On Fri, 30 May 2025 15:54:34 GMT, Alan Bateman <alanb at openjdk.org> wrote:

> We should be able to use a buffer that is a view of memory segment allocated from shared arena, only the confined case should throw UOE.

I ran into this in testing:

    public long address() {
        MemorySessionImpl session = session();
        if (session != null) {
            if (session.ownerThread() == null && session.isCloseable()) {
                throw new UnsupportedOperationException("ByteBuffer derived from closeable shared sessions not supported");
            }
 ```
in `Direct-X-Buffer.java.template` when using the result of `Arena.ofShared`.

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PR Comment: https://git.openjdk.org/jdk/pull/25531#issuecomment-2922822498