Hi @tony10012,
The example for Wrapping a native rosjava node has been updated recently with a simple example, wrapping a native publisher as a rosjava node, and showing how to execute it. Please take a look there.
As @ecorbellini points out, the technique works out for Android and for pure rosjava, but if you are not using it on Android, using the cross compiled library would seem a simpler solution to me.