Accessing a ByteBuffer in DLL with JNI

Is it possible to get access to the memory location of the data for a direct ByteBuffer passed into a DLL using JNI? It would be a lot more efficient than using its read-write methods.

you mean like this:
http://java.sun.com/j2se/1.4.2/docs/guide/jni/jni-14.html#NewDirectByteBuffer

?

yes