[jboss-jira] [JBoss JIRA] Created: (JASSIST-99) Javassist causes java.lang.ClassFormatError: Invalid length 561 in LocalVariableTable in class file

[Martin Burger (JIRA)]

Javassist causes java.lang.ClassFormatError: Invalid length 561 in LocalVariableTable in class file
---------------------------------------------------------------------------------------------------

                 Key: JASSIST-99
                 URL: https://jira.jboss.org/jira/browse/JASSIST-99
             Project: Javassist
          Issue Type: Bug
    Affects Versions: 3.11.0.GA
            Reporter: Martin Burger
            Assignee: Shigeru Chiba


I am instrumenting field accesses in Java classes. Unfortunately, this fails in some cases, the manipulated byte code causes a java.lang.ClassFormatError:

Exception in thread "main" java.lang.ClassFormatError: Invalid length 561 in LocalVariableTable in class file de/unisb/cs/st/deltadebugging/jinsi/test/integration/events/outgoing/fieldaccesses/SuperClassOfObserved
        at java.lang.ClassLoader.defineClass1(Native Method)
        ...

This issue occurred in 3.11.0.GA and is not fixed in r505. Maybe this is related to JASSIST-98. In 3.10.0.GA, this issue does not exist, the affected class can be loaded without any error.

I tried to analyze the corrupt class file with javassist.tools.framedump, but the analysis fails:

Exception in thread "main" java.lang.RuntimeException: javassist.bytecode.BadBytecode: Could not find class in descriptor [pos = 8]: de.unisb.cs.st.deltadebugging.jinsi.test.integration.events.outgoing.fieldaccesses.Unobserved
        at javassist.bytecode.analysis.FramePrinter.print(FramePrinter.java:89)
        ...

I decompiled both classes (the working one and the corrupt one) using JAD, the output differs slightly:

43c43
< /*  16*/        JVM INSTR new #96  <Class Long>;
---
> /*  16*/        JVM INSTR new #102 <Class Long>;
59c59
< /*  16*/        JVM INSTR new #96  <Class Long>;
---
> /*  16*/        JVM INSTR new #102 <Class Long>;

Here is the corrupt decompiled code of line 16. Compared to the working class, lines 43 and 59 seem to be switched:

    28	/*  16*/        obj = this;
    29	/*  16*/        Unobserved unobserved1 = null;
    30	/*  16*/        unobserved1 = ((SuperClassOfObserved) (obj)).unobserved;
    31	/*  16*/        EventRecorderFactory.getInstance().recordOutgoingFieldRead(this, JinsiClassUtils.getClassOfObject(this), obj, Desc.getClazz("de.unisb.cs.st.deltadebugging.jinsi.test.integration.events.outgoing.fieldaccesses.SuperClassOfObserved"), "unobserved", unobserved1, Desc.getType("Lde/unisb/cs/st/deltadebugging/jinsi/test/integration/events/outgoing/fieldaccesses/Unobserved;"), "SuperClassOfObserved.java", 16, Context.METHOD);
    32	/*  16*/        EventRecorderFactory.getInstance().recordIncomingFieldRead(this, JinsiClassUtils.getClassOfObject(this), obj, Desc.getClazz("de.unisb.cs.st.deltadebugging.jinsi.test.integration.events.outgoing.fieldaccesses.SuperClassOfObserved"), "unobserved", unobserved1, Desc.getType("Lde/unisb/cs/st/deltadebugging/jinsi/test/integration/events/outgoing/fieldaccesses/Unobserved;"), "SuperClassOfObserved.java", 16, Context.METHOD);
    33	/*  16*/        obj = unobserved1;
    34	/*  16*/        l = 0L;
    35	/*  16*/        l = ((Unobserved) (obj)).fieldLong;
    36	/*  16*/        EventRecorderFactory.getInstance();
    37	/*  16*/        this;
    38	/*  16*/        JinsiClassUtils.getClassOfObject(this);
    39	/*  16*/        obj;
    40	/*  16*/        Desc.getClazz("de.unisb.cs.st.deltadebugging.jinsi.test.integration.events.outgoing.fieldaccesses.Unobserved");
    41	/*  16*/        "fieldLong";
    42	/*  16*/        l;
    43	/*  16*/        JVM INSTR new #102 <Class Long>;
    44	/*  16*/        JVM INSTR dup ;
    45	/*  16*/        Long();
    46	/*  16*/        Desc.getType("J");
    47	/*  16*/        "SuperClassOfObserved.java";
    48	/*  16*/        16;
    49	/*  16*/        Context.METHOD;
    50	/*  16*/        recordOutgoingFieldRead();
    51	/*  16*/        JVM INSTR pop ;
    52	/*  16*/        EventRecorderFactory.getInstance();
    53	/*  16*/        this;
    54	/*  16*/        JinsiClassUtils.getClassOfObject(this);
    55	/*  16*/        obj;
    56	/*  16*/        Desc.getClazz("de.unisb.cs.st.deltadebugging.jinsi.test.integration.events.outgoing.fieldaccesses.Unobserved");
    57	/*  16*/        "fieldLong";
    58	/*  16*/        l;
    59	/*  16*/        JVM INSTR new #102 <Class Long>;
    60	/*  16*/        JVM INSTR dup ;
    61	/*  16*/        Long();
    62	/*  16*/        Desc.getType("J");
    63	/*  16*/        "SuperClassOfObserved.java";
    64	/*  16*/        16;
    65	/*  16*/        Context.METHOD;
    66	/*  16*/        recordIncomingFieldRead();
    67	/*  16*/        JVM INSTR pop ;
    68	/*  16*/        long fieldLong = l;

However, I don't know if this is related to the defect.

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