Bytecode Instrumentation

| 2004 JavaOne

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

java_crw_demo BCI Library

• Non-instrumented methods

─ init methods

─ finalize methods whose length is 1

─ "system" classes clinit methods

─ java.lang.Thread.currentThread()

•

Modifications

─ No methods or fields added to any class

─ Only add new constant pool entries at end of original constant pool table

─ Exception, line, and local variable tables for each method adjusted

─ Bytecode optimization to use

─ Smaller offsets

─ Fewest 'wide' opcodes

•

Goals

─ Minimize number of bytecodes at each injection site

─ Classes with N return opcodes or N newarray opcodes will get N

injections

─ Input arguments to java_crw_demo determine injections made