[Sablevm-developer] Found deadlock in Class.getConstructor(Class[]).newInstance(Objects[])

[Clemens E. <lin...@we...>]

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