Clarified in JavaDocs that implementation uses off-heap memory

src/java.base/share/classes/sun/nio/ch/SocketChannelImpl.java

@@ -1640,7 +1640,7 @@ public String toString() {
  * value differently.
  *
  * @implSpec
- * The {@code skip} method implementation of this class creates a
+ * The {@code skip} method implementation of this class creates an off-heap
  * byte array and then repeatedly reads into it until {@code n} bytes
  * have been read or the end of the stream has been reached. Subclasses are
  * encouraged to provide a more efficient implementation of this method.

src/java.base/unix/classes/sun/nio/ch/SourceChannelImpl.java

@@ -375,7 +375,7 @@ public long read(ByteBuffer[] dsts) throws IOException {
  * value differently.
  *
  * @implSpec
- * The {@code skip} method implementation of this class creates a
+ * The {@code skip} method implementation of this class creates an off-heap
  * byte array and then repeatedly reads into it until {@code n} bytes
  * have been read or the end of the stream has been reached. Subclasses are
  * encouraged to provide a more efficient implementation of this method.

src/java.base/windows/classes/sun/nio/ch/SourceChannelImpl.java

@@ -151,7 +151,7 @@ public long read(ByteBuffer[] dsts) throws IOException {
  * value differently.
  *
  * @implSpec
- * The {@code skip} method implementation of this class creates a
+ * The {@code skip} method implementation of this class creates an off-heap
  * byte array and then repeatedly reads into it until {@code n} bytes
  * have been read or the end of the stream has been reached. Subclasses are
  * encouraged to provide a more efficient implementation of this method.