Bytecode Instrumentation

| 2004 JavaOne

Conference | Session 3042 Copyright Hewlett Packard Co., 2004.

Start-up Using JVMTI

•

Start-up

─ -agentlib:<agent-lib-name>=<options>

─ Agent_OnLoad() called when library loaded

─ Set-up the callbacks

jvmtiEventCallbacks callbacks;

Callbacks.ClassFileLoadHook =

&cbClassFileLoadHook

;

─ Load the java_crw_demo native BCI library

•

Application running

─ When class loaded (or reloaded):

─ Callback made to cbClassFileLoadHook()

– Generate unique class identification number

– Instrument bytecode

– Supply Java method(s) to call from instrumentation

– Return modified class file