Thread: [Sablevm-developer] Re: Sablevm-developer digest, Vol 1 #366 - 11 msgs

SourceForge Headquarters 225 Broadway Suite 1600 San Diego, CA 92101 +1 (858) 422-6466

I see a motivation to incorporate my work of "Deadlock Resolution via
Exceptions for Dependable Java Applications" into SableVM. Anyone
interested in co-working with me in implementing deadlock exceptions for
SableVM? 

--

Fancong Zeng
Department of Computer Science
Rutgers University
Piscataway, NJ, 08854

(732)445-6994
http://www.cs.rutgers.edu/~fzeng

> Message: 8
> Date: Thu, 15 Apr 2004 12:45:37 -0400
> From: Etienne Gagnon <gag...@uq...>
> Organization: UQAM
> To: Clemens Eisserer <lin...@we...>
> CC: sab...@li...
> Subject: Re: [Sablevm-developer] Found deadlock in Class.getConstructor(Class[]).newInstance(Objects[])
> 
> Hi Clemens,
> 
> SableVM will dump a stack trace during execution when you cause a SIGQUIT
> signal.  On most systems you do this by pressing Ctrl-\ (Control key and "\"
> key together).  It gives much more information than a simple gdb stack dump
> which does not tell us about the content of the Java stack.
> 
> I you have time, it would be grat if you also sent a minimal complete piece
> of code that I could simply "compile and run" to exhibit the problem.
> 
> have fun!
> 
> Etienne
> 
> Clemens Eisserer wrote:
> > Hello again!
> > 
> > After reinstalling my whole gtk/gdk/atk/pango rpms your build-system now 
> > even worked on my system.
> > 
> > I'm trying to use a lightweight gui library called "lwvcl", which is 
> > based on a swingle awt.component.
> > At initialisation it does load some classes via class.forName and does 
> > some other class-based stuff.
> > I think I've found a deadlock in 
> > Class.getConstructor(Class[]).newInstance(Objects[]).
> > 
> > As you can see with this piece if code several different classes where 
> > loaded (some of them many times), but suddenly the method hangs when
> > 
> > Here's the classname and the argument-type's list:
> > 
> > So geladen:java.lang.String java.lang.String
> > So geladen:java.lang.String java.lang.String
> > So geladen:java.lang.String java.lang.String
> > So geladen:LwBorder int
> > So geladen:LwBorder int
> > So geladen:LwBorder int
> > So geladen:LwBorder int
> > So geladen:LwBorder int
> > So geladen:LwBorder int
> > So geladen:LwImgSetRender java.lang.String int int int int int
> > So geladen:LwImgSetRender java.lang.String int int int int int
> > So geladen:LwImgSetRender java.lang.String int int int int int
> > So geladen:LwImgSetRender java.lang.String int int int int int
> > So geladen:LwImgSetRender java.lang.String int int int int int
> > So geladen:LwImgSetRender java.lang.String int int int int int
> > So geladen:LwImgSetRender java.lang.String int int int int int
> > So geladen:LwImgSetRender java.lang.String int int int int int
> > So geladen:LwImgSetRender java.lang.String int int int int int         
> > <-----  Deadlock here
> > 
> > 
> > I tried to debug it using gdb, but unlike without gdb I get a segfault.
> > Here's the stacktrace:
> > 
> > Program received signal SIGSEGV, Segmentation fault.
> > [Switching to Thread 16384 (LWP 2897)]
> > _svmf_interpreter (_env=0x0) at interpreter.c:266
> > 266         _svmt_method_info *method = frame->method;
> > (gdb) bt
> > #0  _svmf_interpreter (_env=0x0) at interpreter.c:266
> > #1  0x40083491 in JNI_CreateJavaVM (pvm=0xbffff1e0, penv=0xbffff1e4,
> >    _vm_args=0xbffff1f0) at invoke_interface.c:293
> > #2  0x08049e68 in main (argc=0, argv=0x0) at sablevm.c:1351
> > 
> > 
> > And here's the method of the gui library that calls the deadlock-method:
> > 
> > /**
> >  * Creates an instance of the specified class using appropriate 
> > constructor for the given input arguments list.
> >  * The list is set of arguments that are separated by the comma. The 
> > following arguments types can be
> >  * used:
> >  * <ul>
> >  *   <li>Integer. If the argument does not equal "true" or "false" and  
> > is not bound by quotes.</li>
> >  *   <li>Boolean. If the argument equals "true" or "false" and is not 
> > bound by quotes.</li>
> >  *   <li>String. If the argument is not bound by quote.</li>
> >  * </ul>
> >  * @param <code>className</code> the specified class name.
> >  * @param <code>argsStr</code> the specified input arguments list. The 
> > argument can be <code>null</code>.
> >  * In this case the default constructor will be used to create the class 
> > instance.
> >  * @return an instance of the class.
> >  */
> >  public static Object createObj(String className, String argsStr)
> >  throws Exception
> >  {
> >      if (className.indexOf ('@') == 0) return 
> > getStaticObj(className.substring(1));
> >      else
> >      {
> >        Class  classInstance = 
> > Class.forName(className.indexOf('.')>0?className:PACKAGE_NAME + className);
> >    Object objInstance   = null;
> >    if (argsStr == null)
> >        {
> >          objInstance = classInstance.newInstance();
> >        }
> >        else
> >        {
> >          StringTokenizer args       = new StringTokenizer(argsStr, ",");
> >          Class[]         argsTypes  = new Class [args.countTokens()];
> >          Object[]        argsValues = new Object[argsTypes.length];
> >          for (int j = 0; args.hasMoreTokens(); j++)
> >          {
> >            String arg = args.nextToken().trim();
> >            if (arg.indexOf('\"')==0)
> >            {
> >              argsTypes [j] = String.class;
> >              argsValues[j] = arg.substring(1, arg.length() - 1);
> >            }
> >            else
> >            if (arg.equals("true") || arg.equals("false"))
> >            {
> >              argsTypes [j] = Boolean.TYPE;
> >              argsValues[j] = new Boolean(arg);
> >            }
> >            else
> >            if (arg.indexOf('@') == 0)
> >            {
> >              argsValues[j] = getStaticObj(arg.substring(1));
> >              argsTypes [j] = argsValues[j].getClass();
> >            }
> >            else
> >            {
> >              argsTypes [j] = Integer.TYPE;
> >              argsValues[j] = new Integer(arg);
> >            }
> >          }
> >          System.out.print("So geladen:"+className);
> >          for(int i=0; i < argsTypes.length; i++)
> >          {
> >            System.out.print(" "+argsTypes[i].getName());
> >          }
> >          System.out.println();
> >          objInstance = 
> > classInstance.getConstructor(argsTypes).newInstance(argsValues);
> >        }
> >        return objInstance;
> >      }
> >  }
> > 
> > 
> > Maby this code isn't written well, however it works even with the 
> > Microsoft-JVM ;-)
> > 
> > Hope this helped, lg Linuxhippy
> > 

Thread: [Sablevm-developer] Re: Sablevm-developer digest, Vol 1 #366 - 11 msgs

sablevm-developer