Summary

Modify the specification of the minBufferCap parameter of the principal, three-parameter variant of java.nio.channels.Channels.newWriter to indicate that it is ignored.

Problem

The implementation of this variant of Channels.newWriter allowed for problematic behavior and required duplicate implementations for OutputStream and WritableByteChannel.

Solution

Remove WritableByteChannel support in StreamEncoder and instead use an OutputStream that wraps a WritableByteChannel.

Specification

--- a/src/java.base/share/classes/java/nio/channels/Channels.java
+++ b/src/java.base/share/classes/java/nio/channels/Channels.java
@@ -521,20 +521,24 @@
      * channel; if the channel is in non-blocking mode when bytes are to be
      * written then an {@link IllegalBlockingModeException} will be thrown.
      * The resulting stream will not otherwise be buffered.  Closing the stream
      * will in turn cause the channel to be closed.  </p>
      *
+     * @implNote
+     * The value of {@code minBufferCap} is ignored.
+     *
      * @param  ch
      *         The channel to which bytes will be written
      *
      * @param  enc
      *         The charset encoder to be used
      *
      * @param  minBufferCap
      *         The minimum capacity of the internal byte buffer,
      *         or {@code -1} if an implementation-dependent
-     *         default capacity is to be used
+     *         default capacity is to be used. The value of
+     *         {@code minBufferCap} may be ignored
      *
      * @return  A new writer
      */
     public static Writer newWriter(WritableByteChannel ch,
                                    CharsetEncoder enc,