'light_jni' - allows to call some predefined JNI methods directly, without use of JNI stub.
If a JNI method does not use Java environment it can be called directly without creation of JNI stub.
In this case NULL is passed as a parameter to a method instead of JNIEnv*.
By default the optimization works only for hardcoded set of known methods. To make it work for your method, use the following command line option:
-XX:jit.arg.codegen.light_jni.light_jni_methods=my/Method.foo1,my/Method.foo2
implementation file: http://svn.apache.org/viewvc/harmony/enhanced/drlvm/trunk/vm/jitrino/src/codegenerator/ia32/Ia32LightJNI.cpp