public void invokeVirtual(String owner, String name, String desc) {
   super.visitMethodInsn(INVOKEVIRTUAL, owner, name, desc);
 }
 public void println(String msg) {
   super.visitFieldInsn(GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");
   ldc(msg);
   super.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V");
 }