MethodInfo minfo = new MethodInfo(cp, GETFIELDHANDLER_METHOD_NAME,
GETFIELDHANDLER_METHOD_DESCRIPTOR);
/* local variable | this | */
Bytecode code = new Bytecode(cp, 2, 1);
// aload_0 // load this
code.addAload(0);
// getfield // get field "$JAVASSIST_CALLBACK" defined already
code.addOpcode(Opcode.GETFIELD);
int field_index = cp.addFieldrefInfo(this_class_index,
HANDLER_FIELD_NAME, HANDLER_FIELD_DESCRIPTOR);
code.addIndex(field_index);