ClassloadingUtil.class.getClassLoader() returns null

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jda...@redhat.com

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Apr 10, 2017, 12:03:51 PM4/10/17

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I noticed that the .getClassLoader() method in JPF is currently implemented to return null. My program relies on this.

What could be done about it, besides changing my program?

Nastaran Shafiei

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Apr 10, 2017, 3:05:50 PM4/10/17

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Are you referring to the getClassLoader method in Class? This method is not set to return null - it captures similar behavior to its counterpart from Java standard libraries.

Nastaran

On Apr 10, 2017, at 9:03 AM, jda...@redhat.com wrote:

I noticed that the .getClassLoader() method in JPF is currently implemented to return null. My program relies on this.

What could be done about it, besides changing my program?

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jda...@redhat.com

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Apr 11, 2017, 5:56:36 PM4/11/17

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On Monday, April 10, 2017 at 9:05:50 PM UTC+2, nastaran wrote:

Are you referring to the getClassLoader method in Class? This method is not set to return null - it captures similar behavior to its counterpart from Java standard libraries.

Nastaran

You are correct, I made a mistake when reading the stacktrace

The SUT code in question is

public static Object newInstanceFromClassLoader(final String className) {

ClassLoader loader = ClassloadingUtil.class.getClassLoader();
try {

Class<?> clazz = loader.loadClass(className);
return clazz.newInstance();

} catch (Throwable t) {

t.printStackTrace();
if (t instanceof InstantiationException) {

System.out.println(INSTANTIATION_EXCEPTION_MESSAGE);

}
loader = Thread.currentThread().getContextClassLoader();
if (loader == null)

throw new RuntimeException("No local context classloader", t);

....

I got the exception "No local context classloader" exception from the last line in the listing.

#getClassLoader is completely fine, the problem is #getContextClassLoader which is programmed to always return null in JPF

 public class Thread implements Runnable {
 ...
      public ClassLoader getContextClassLoader () {
          // <NSY>
          return null;
      }

(what does NSY stand for?)

I am not sure if my SUT actually needs #getContextClassLoader for its normal operations. Currently, I am inclined to believe I just had a bad luck to pick a JUnit test which needed this. When I moved to different test, this problem did not arise.

Anyways, my current exception is (with jpf-nhandler)

* DELEGATING Unhandled Native -> sun.management.OperatingSystemImpl.initialize

[SEVERE] JPF exception, terminating: exception in native method sun.management.OperatingSystemImpl.initialize

java.lang.UnsatisfiedLinkError: sun.management.OperatingSystemImpl.initialize()V

at sun.management.OperatingSystemImpl.initialize(Native Method)

at sun.management.OperatingSystemImpl.<clinit>(OperatingSystemImpl.java:54)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at OTF_JPF_sun_management_OperatingSystemImpl.initialize____V(OTF_JPF_sun_management_OperatingSystemImpl.class)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at gov.nasa.jpf.vm.NativeMethodInfo.executeNative(NativeMethodInfo.java:125)

at gov.nasa.jpf.jvm.bytecode.EXECUTENATIVE.execute(EXECUTENATIVE.java:73)

at gov.nasa.jpf.vm.ThreadInfo.executeInstruction(ThreadInfo.java:1908)

at gov.nasa.jpf.vm.ThreadInfo.executeTransition(ThreadInfo.java:1859)

at gov.nasa.jpf.vm.SystemState.executeNextTransition(SystemState.java:765)

at gov.nasa.jpf.vm.VM.forward(VM.java:1722)

at gov.nasa.jpf.search.Search.forward(Search.java:579)

at gov.nasa.jpf.search.DFSearch.search(DFSearch.java:79)

at gov.nasa.jpf.JPF.run(JPF.java:613)

at gov.nasa.jpf.JPF.start(JPF.java:189)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at gov.nasa.jpf.tool.Run.call(Run.java:80)

at gov.nasa.jpf.tool.RunJPF.main(RunJPF.java:116)

---------------------- JPF error stack trace ---------------------

gov.nasa.jpf.JPFNativePeerException: exception in native method sun.management.OperatingSystemImpl.initialize

at gov.nasa.jpf.vm.NativeMethodInfo.executeNative(NativeMethodInfo.java:186)

at gov.nasa.jpf.jvm.bytecode.EXECUTENATIVE.execute(EXECUTENATIVE.java:73)

at gov.nasa.jpf.vm.ThreadInfo.executeInstruction(ThreadInfo.java:1908)

at gov.nasa.jpf.vm.ThreadInfo.executeTransition(ThreadInfo.java:1859)

at gov.nasa.jpf.vm.SystemState.executeNextTransition(SystemState.java:765)

at gov.nasa.jpf.vm.VM.forward(VM.java:1722)

at gov.nasa.jpf.search.Search.forward(Search.java:579)

at gov.nasa.jpf.search.DFSearch.search(DFSearch.java:79)

at gov.nasa.jpf.JPF.run(JPF.java:613)

at gov.nasa.jpf.JPF.start(JPF.java:189)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at gov.nasa.jpf.tool.Run.call(Run.java:80)

at gov.nasa.jpf.tool.RunJPF.main(RunJPF.java:116)

Caused by: java.lang.UnsatisfiedLinkError: sun.management.OperatingSystemImpl.initialize()V

at sun.management.OperatingSystemImpl.initialize(Native Method)

at sun.management.OperatingSystemImpl.<clinit>(OperatingSystemImpl.java:54)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at OTF_JPF_sun_management_OperatingSystemImpl.initialize____V(OTF_JPF_sun_management_OperatingSystemImpl.class)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at gov.nasa.jpf.vm.NativeMethodInfo.executeNative(NativeMethodInfo.java:125)

... 15 more

The funny thing is that I cannot use the GenPeer tool either:

[jdanek@nixos:~/Work/repos/activemq-artemis/tests/stress-tests/target]$ java -cp ~/workspace/jpf-core/build/main gov.nasa.jpf.tool.GenPeer -s -ci -m sun.management.OperatingSystemImpl > ~/workspace/jpf-core/src/peers/gov/nasa/jpf/vm/JPF_sun_management_OperatingSystemImpl.java

java.lang.UnsatisfiedLinkError: sun.management.OperatingSystemImpl.initialize()V

at sun.management.OperatingSystemImpl.initialize(Native Method)

at sun.management.OperatingSystemImpl.<clinit>(OperatingSystemImpl.java:54)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Class.java:264)

at gov.nasa.jpf.tool.GenPeer.getClass(GenPeer.java:75)

at gov.nasa.jpf.tool.GenPeer.main(GenPeer.java:64)

I'll try to deal with this new exception tomorrow and post a new thread if I do not succeed on my own.