VerifyError: Inconsistent args_size for opc_invokeinterface occured for nested statement ---------------------------------------------------------------------------------------- Key: JASSIST-201 URL: https://issues.jboss.org/browse/JASSIST-201 Project: Javassist Issue Type: Bug Affects Versions: 3.17.1-GA Environment: Sun JRE6 1.6.0_25 64bits Reporter: Hua Zhang Assignee: Shigeru Chiba Priority: Critical Labels: VerifyError, nested, opc_invokeinterface Fix For: 3.18.0-GA Please see source in "steps to reproduce". Running the code will throw error: Exception in thread "main" java.lang.VerifyError: (class: Clazz, method: method signature: ()V) Inconsistent args_size for opc_invokeinterface at java.lang.Class.getDeclaredConstructors0(Native Method) at java.lang.Class.privateGetDeclaredConstructors(Unknown Source) at java.lang.Class.getConstructors(Unknown Source) at test.<init>(test.java:27) at test.main(test.java:31) The key is on "new HashMap().toString()" in the statement: theMethod.setBody("{map.put(\"name\", new HashMap().toString());System.out.println(\"OK\");}"); The behaviour is really strange. Try to modify it, sometimes it can be run successfully, sometimes failed. But they all can be compiled successfully. FAILED: theMethod.setBody("{StringBuffer buffer = new StringBuffer();map.put(\"name\", buffer.toString());System.out.println(\"OK\");}"); SUCCESS: theMethod.setBody("{map.put(\"name\", map.toString());System.out.println(\"OK\");}"); SUCCESS: (workaround) theMethod.setBody("{String V = new HashMap().toString();map.put(\"name\", V);System.out.println(\"OK\");}");