* java/nio/MappedByteBuffer.java: (forceImpl, isLoadedImpl, loadImpl,
unmapImpl): New dummy methods, to be overridden by subclass.
(finalize, isLoaded, load, force): New methods.
* java/nio/MappedByteBufferImpl.java: More-or-less rewrite.
Now works, at least for read mapping.
From-SVN: r78662
