title: How to obtain JNI interface pointer (JNIEnv *) for asynchronous calls
body: <p>I have learned that the JNI interface pointer (JNIEnv *) is only valid in the current thread. Suppose I started a new thread inside a native method; how it can asynchronously send events to a Java method? As this new thread can't have a reference of (JNIEnv *). Storing a global variable for (JNIEnv *) apparently will not work?</p>