// check the found method
affirm(!method.isAbstract(),
"Attempt to add code to an abstract method.");
affirm(!method.isNative(),
"Attempt to add code to a native method.");
final CodeAttribute foundCodeAttr = method.codeAttribute();
affirm(foundCodeAttr != null); // by JVM spec
// prepend the new code to the current one
final Insn firstInsn = codeAttr.theCode();
affirm(firstInsn != null);