------- part of test code -------------
// fc (FileChanne) and mapSize is already initialized
MappedByteBuffer b = fc.map(FileChannel.MAP_RW, 0, mapSize);
System.out.println("MappedByteBuffer = " + b );
System.out.println("isLoaded():" + b.isLoaded());

--------- results -------------------
% javac FCmap.java
% java FCmap

MappedByteBuffer = java.nio.DirectByteBuffer[pos=0 lim=3043 cap=3043]
Exception in thread "main" java.lang.UnsatisfiedLinkError: isLoaded0
        at java.nio.MappedByteBuffer.isLoaded0(Native Method)
        at java.nio.MappedByteBuffer.isLoaded(MappedByteBuffer.java:126)
        at FCmap.MBBTest01(FCmap.java:159)
        at FCmap.go(FCmap.java:77)
        at FCmap.main(FCmap.java:54)

-----------------------
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-internal-b57)
Java HotSpot(TM) Client VM (build 1.4.0-beta-b57, mixed mode)