Method ID

Hi,
For sake of profiling, I want to record some unique number for each method invoked by the java code. I am modifying the JVM CPP interpreter  and was wondering about what value I should use as an ID for a method that doesn't change throughout execution. I don't want to rely on method name + signature. For now, I use the jmethodID object address, I am not sure if it remains unchanged or not.

thanks,
- nagy