RFR: 6400876: (bf) Remove sun.nio.ByteBuffered and releated obsolete code

[Daniel Jeliński]

On Tue, 28 Oct 2025 10:18:57 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

> Can I please get a review of this change which removes an obsolete internal interface?
> 
> The `sun.nio.ByteBuffered` interface is internal to the java.base module and does not have any implementations in the JDK. The only place where we use this is in `jdk.internal.loader.Resource` (another internal class within java.base). The usage itself is a mere `instanceof` check against the `InputStream` corresponding to that `Resource`. Given that there are no implementations of this interface, that check is redundant.
> 
> tier testing is currently in progress with this change, and given the nature of this change, no new tests have been introduced.

Nice cleanup!

[This line](https://github.com/openjdk/jdk/blob/9625993611bb6acf84d428bea4a65d33b9d66e5f/test/micro/org/openjdk/bench/jdk/internal/jrtfs/ImageReaderBenchmark.java#L1065) should probably be removed.

src/java.base/share/classes/jdk/internal/loader/Resource.java line 133:

> 131:      */
> 132:     public ByteBuffer getByteBuffer() throws IOException {
> 133:         InputStream in = cachedInputStream();

The method documentation could use a cleanup as well.

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PR Review: https://git.openjdk.org/jdk/pull/28016#pullrequestreview-3387970929
PR Review Comment: https://git.openjdk.org/jdk/pull/28016#discussion_r2468960413