final ConstantPoolGen cpg = classGen.getConstantPool();
final InstructionList il = methodGen.getInstructionList();
il.append(DUP);
final BranchHandle ifNull = il.append(new IFNULL(null));
il.append(new INVOKEVIRTUAL(cpg.addMethodref(_javaClassName,
"toString",
"()" + STRING_SIG)));
final BranchHandle gotobh = il.append(new GOTO(null));
ifNull.setTarget(il.append(POP));
il.append(new PUSH(cpg, ""));