title: Blocking operation dn't work in Jni Layer function call
body: <p>i have write down a C++ to java call using jni layer.
  in java i have to load some big size xml using dom4j at the start.
  when it goes for loading, process return back to C++ code, without loading the xml;
  Do Jni don't work with blocking operation, 
  any input will be appreciable.</p>