[Joeq-devel] NullPointerException in monitorenter.java (Bug?)

[David A. R. <dtr...@um...>]

Hi Everyone,

I've spent the greater part of this week trying to run a graphical  
Java application inside Joeq (native mode) on Linux 2.6.9-67.0.1.ELsmp  
with Sun JDK 1.5.0_01.  My main problem is that System.loadLibrary is  
not working properly when attempting to load the awt library.  I fixed  
one bug already in  
joeq_native/joeq/ClassLib/sun14_linux/java/lang/System.java by  
implementing mapLibraryName correctly.

The application gets as far as executing ClassLoader.loadLibrary0, and  
executes the statement "synchronized(loadedLibraryNames){" (JDK1.5's  
java/lang/ClassLoader.java:1714).  This triggers  
joeq.Runtime.Monitor.monitorenter(Object k), which crashes on a  
NullPointerException because k is null.  However, loadedLibraryNames  
is an initialized static field inside JDK's ClassLoader class.  So how  
can it be null?  I suspect that the problem has to do with the various  
overloaded versions of ClassLoader inside Joeq, but I have not been  
able to fix it.  Below is a copy of the exception backtrace.  Please  
note that the line number for Monitor.java is off because I've added  
debug statements to pinpoint the problem.

Has anyone successfully loaded shared JNI libraries from inside native  
Joeq?  Also, is there a good way to debug native Joeq?  GDB won't do  
much unless there's a seg fault.

Thanks in advance!
-David

java.lang.ExceptionInInitializerError
         at java.lang.Throwable.fillInStackTrace(Throwable.java:57)
         at java.lang.Throwable.<init>(Throwable.java:181)
         at java.lang.Error.<init>(Error.java:37)
         at java.lang.LinkageError.<init>(LinkageError.java:26)
         at  
java.lang.ExceptionInInitializerError.<init>(ExceptionInInitializerError.java:61)
         at joeq.Class.jq_Class.invokeclinit(jq_Class.java:2448)
         at joeq.Class.jq_Class.cls_initialize(jq_Class.java:2431)
         at  
joeq.Compiler.Reference.x86.x86ReferenceLinker.invokestatic(x86ReferenceLinker.java:183)
         at java.awt.Component.<clinit>(Component.java:545)
         at joeq.Runtime.ReflectionImpl.invokestatic_V(ReflectionImpl.java:326)
         at  
joeq.Compiler.Reference.x86.x86ReferenceLinker.invokeinterface(x86ReferenceLinker.java:220)
         at joeq.Runtime.Reflection.invokestatic_V(Reflection.java:100)
         at joeq.Class.jq_Class.invokeclinit(jq_Class.java:2442)
         at joeq.Class.jq_Class.cls_initialize(jq_Class.java:2431)
         at joeq.Class.jq_Class.cls_initialize(jq_Class.java:2427)
         at joeq.Class.jq_Class.cls_initialize(jq_Class.java:2427)
         at joeq.Class.jq_Class.cls_initialize(jq_Class.java:2427)
         at joeq.Class.jq_Class.cls_initialize(jq_Class.java:2427)
         at joeq.Main.JoeqVM.boot(JoeqVM.java:216)
Caused by: java.lang.NullPointerException
         at java.lang.Throwable.fillInStackTrace(Throwable.java:57)
         at java.lang.Throwable.<init>(Throwable.java:181)
         at java.lang.Exception.<init>(Exception.java:29)
         at java.lang.RuntimeException.<init>(RuntimeException.java:32)
         at java.lang.NullPointerException.<init>(NullPointerException.java:36)
         at  
joeq.Runtime.ExceptionDeliverer.trap_handler(ExceptionDeliverer.java:50)
         at joeq.Runtime.Monitor.monitorenter(Monitor.java:64)
         at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1714)
         at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1668)
         at java.lang.Runtime.loadLibrary0(Runtime.java:822)
         at java.lang.System.loadLibrary(System.java:49)
         at  
sun.security.action.LoadLibraryAction.run(LoadLibraryAction.java:50)
         at  
joeq.Compiler.Reference.x86.x86ReferenceLinker.invokeinterface(x86ReferenceLinker.java:220)
         at  
java.security.AccessController.doPrivileged(AccessController.java:16)
         at sun.awt.NativeLibLoader.loadLibraries(NativeLibLoader.java:38)
         at sun.awt.DebugHelper.<clinit>(DebugHelper.java:29)
         at joeq.Runtime.ReflectionImpl.invokestatic_V(ReflectionImpl.java:326)
         at  
joeq.Compiler.Reference.x86.x86ReferenceLinker.invokeinterface(x86ReferenceLinker.java:220)
         at joeq.Runtime.Reflection.invokestatic_V(Reflection.java:100)
         at joeq.Class.jq_Class.invokeclinit(jq_Class.java:2442)
         ... 13 more