Bytecode instrumentation system classes in Java with ASM
<p>My javaagent, run via -javagent, instruments classes with callbacks to static methods on one of my classes.  This works great, apart from on system classes, e.g. java/lang, java/util, which throw ClassDefNotFounderror at the point when the method is called (with INVOKESTATIC).  So it appears they are instrumented, because the method call is attempted, but have an access or visibility issue that my user classes don't have.  My callback class and its methods are all public.</p>

<p>I've tried adding my class to the classpath (instead of just loading via -javaagent) but that didn't help.  Is there some protection of system classes I need to override?</p>
