Label label = new Label();
mv.visitJumpInsn(IFLT, label);
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ILOAD, 1);
mv.visitFieldInsn(PUTFIELD, "pkg/Bean", "f", "I");
mv.visitInsn(RETURN);
mv.visitLabel(label);
mv.visitFrame(F_SAME, 0, null, 0, null);
mv.visitTypeInsn(NEW, "java/lang/IllegalArgumentException");
mv.visitInsn(DUP);
mv.visitMethodInsn(INVOKESPECIAL,