Name: tb29552 Date: 08/26/2004


FULL PRODUCT VERSION :
java version "1.5.0-beta3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta3-b60)
Java HotSpot(TM) Client VM (build 1.5.0-beta3-b60, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Linux deepspace1 2.4.22-10mdk #1 Thu Sep 18 12:30:58 CEST 2003 i686 unknown unknown GNU/Linux

A DESCRIPTION OF THE PROBLEM :
I have added a very simple example, that reproduces the problem:

The class (test.Startup) contains the instrumentation. It does nothing but replace the loaded class "test.Instrumented" with a new version (which is exactly the same as the old version). The loaded byte arrays is dumped to a file, so it is possible to compare it to the original classfile.

After reloading the class, invoking the constructor of "test.Instrumented" leads to a VerifyError. But since the classfile is exactly the same as before this should not happen.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1.) Make a directory "test"
2.) Create the three java files in this directory ("Startup.java", "Instrumentation.java", "Test.java")
3.) Save the manifest as "manifest.mf"
3.) Compile the classes
javac test/*.java
4.) Build the jar file
jar -cvfm test.jar manifest.mf test/Startup.class
5.) Run the Test
java -classpath . -javaagent:test.jar test.Test
6.) A VerifyError is thrown.
7.) Observe that result.dump has exactly the same contents as test/Instrumentation.class

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No Exception.
ACTUAL -
An VerifyError is thrown.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.lang.VerifyError: (class: test/Instrument, method: <init> signature: ()V) Illegal constant pool index
        at test.Test.main(Test.java:12)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
----------------------------------------------
Instrumented.java:
----------------------------------------------
package test;

public class Instrument {
}
----------------------------------------------
Startup.java:
----------------------------------------------
package test;

import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.IOException;
import java.io.ByteArrayOutputStream;
import java.lang.instrument.Instrumentation;
import java.lang.instrument.ClassDefinition;

public class Startup {
    private static Instrumentation instrumentation;

    public static void premain(String options, Instrumentation instrumentation) {
        Startup.instrumentation = instrumentation;
    }

    public static void init()
        throws Exception {
 
        Class[] allClasses = instrumentation.getAllLoadedClasses();
  
        for (int i=0; i<allClasses.length; i++) {
            String className = allClasses[i].getName();
            if ("test.Instrument".equals(className)) {
                byte[] classfileBuffer = getClassFileBuffer(className, allClasses[i].getClassLoader());
                instrumentation.redefineClasses(new ClassDefinition[] {new ClassDefinition(allClasses[i], classfileBuffer)});

                FileOutputStream fout = new FileOutputStream("result.dump");
                fout.write(classfileBuffer);
                fout.close();
            }
         }
    }

    private static final byte[] getClassFileBuffer(String className, ClassLoader cl) throws IOException {
        InputStream is = cl.getResourceAsStream(className.replace('.', '/') + ".class");
        byte[] buf = new byte[1024];

        ByteArrayOutputStream baos = new ByteArrayOutputStream(is.available());
        int read;
        do {
            read = is.read(buf);
            if (read > -1) {
                baos.write(buf, 0, read);
            }
        } while (read > -1);

        is.close();
        return baos.toByteArray();
    }
}
 
----------------------------------------------
Test.java:
----------------------------------------------
package test;

public class Test {

    public static void main(String[] args) throws Exception {
        // load the class
        System.out.println(Instrument.class.getName());

        Startup.init();

        // try to use it again -> causes VerifyError
        new Instrument();
    }
}
----------------------------------------------
manifest.mf:
----------------------------------------------
premain-class: test.Startup
Can-Redefine-Classes: true


---------- END SOURCE ----------
(Incident Review ID: 300972)
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###@###.### 10/7/04 00:12 GMT