Program: 91880
Project: 91880
Buggy source:
@Override public Object execute(ExecutionEvent event) throws ExecutionException {
  IWorkbenchWindow window=PlatformUI.getWorkbench().getActiveWorkbenchWindow();
  if (window == null) {
    return null;
  }
  IWorkbenchPage page=PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
  IWorkbenchPart part=page.getActivePart();
  if (part == null) {
    return Boolean.FALSE;
  }
  ISelectionProvider selectionProvider=part.getSite().getSelectionProvider();
  if (selectionProvider == null) {
    return Boolean.FALSE;
  }
  ISelection selection=selectionProvider.getSelection();
  fSelection=null;
  final ArrayList<TmfTraceElement> tl=new ArrayList<>();
  final ArrayList<TmfExperimentElement> uiexperiment=new ArrayList<>();
  if (selection instanceof TreeSelection) {
    fSelection=(TreeSelection)selection;
    Iterator<Object> iterator=fSelection.iterator();
    while (iterator.hasNext()) {
      Object element=iterator.next();
      if (element instanceof TmfTraceElement) {
        tl.add((TmfTraceElement)element);
      }
 else       if (element instanceof TmfExperimentElement) {
        TmfExperimentElement exp=(TmfExperimentElement)element;
        uiexperiment.add(exp);
        for (        TmfTraceElement trace : exp.getTraces()) {
          tl.add(trace);
        }
      }
    }
  }
  if ((uiexperiment.size() == 1) && (tl.size() > 1)) {
    Thread thread=new Thread(){
      @Override public void run(){
        final ITmfTrace[] traces=new ITmfTrace[tl.size()];
        final TmfExperimentElement exp=uiexperiment.get(0);
        for (int i=0; i < tl.size(); i++) {
          ITmfTrace trace=tl.get(i).instantiateTrace();
          ITmfEvent traceEvent=tl.get(i).instantiateEvent();
          if (trace == null) {
            TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_WrongType + tl.get(i).getName());
            for (int j=0; j < i; j++) {
              traces[j].dispose();
            }
            return;
          }
          try {
            trace.initTrace(tl.get(i).getResource(),tl.get(i).getLocation().getPath(),traceEvent.getClass());
          }
 catch (          TmfTraceException e) {
            TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_InitError + CR + CR+ e);
            trace.dispose();
            for (int j=0; j < i; j++) {
              traces[j].dispose();
            }
            return;
          }
          traces[i]=trace;
        }
        exp.refreshSupplementaryFolder();
        final TmfExperiment experiment=new TmfExperiment(ITmfEvent.class,exp.getName(),traces,exp.getResource());
        try {
          final SynchronizationAlgorithm syncAlgo=experiment.synchronizeTraces(true);
          Display.getDefault().asyncExec(new Runnable(){
            @Override public void run(){
              for (int i=0; i < tl.size(); i++) {
                TmfTraceElement traceel=tl.get(i);
                ITmfTrace expTrace=null;
                for (                ITmfTrace t : experiment.getTraces()) {
                  if (t.getResource().equals(traceel.getResource())) {
                    expTrace=t;
                    break;
                  }
                }
                try {
                  if ((expTrace != null) && syncAlgo.isTraceSynced(expTrace.getHostId())) {
                    TmfTraceElement origtrace=traceel.getElementUnderTraceFolder();
                    if (origtrace != null) {
                      String newname=traceel.getName();
                      IContainer parentFolder=origtrace.getResource().getParent();
                      boolean traceexists;
                      do {
                        traceexists=false;
                        newname+="String_Node_Str";
                        if (parentFolder.findMember(newname) != null) {
                          traceexists=true;
                        }
                      }
 while (traceexists);
                      TmfTraceElement newtrace=origtrace.copy(newname);
                      if (newtrace != null) {
                        ITmfTrace trace=newtrace.instantiateTrace();
                        ITmfEvent traceEvent=newtrace.instantiateEvent();
                        trace.initTrace(newtrace.getResource(),newtrace.getLocation().getPath(),traceEvent.getClass());
                        trace.setTimestampTransform(syncAlgo.getTimestampTransform(trace));
                        exp.addTrace(newtrace);
                        exp.removeTrace(traceel);
                      }
 else {
                        TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_Error + CR + CR+ String.format(Messages.SynchronizeTracesHandler_CopyProblem,origtrace.getName()));
                      }
                    }
                  }
                }
 catch (                CoreException e) {
                  Activator.getDefault().logError(String.format(Messages.SynchronizeTracesHandler_ErrorSynchingForTrace,exp.getName(),traceel.getName()),e);
                  TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_Error + CR + CR+ e.getMessage());
                }
catch (                TmfTraceException e) {
                  Activator.getDefault().logError(String.format(Messages.SynchronizeTracesHandler_ErrorSynchingForTrace,exp.getName(),traceel.getName()),e);
                  TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_Error + CR + CR+ e.getMessage());
                }
              }
            }
          }
);
        }
 catch (        TmfTraceException e) {
          Activator.getDefault().logError(String.format(Messages.SynchronizeTracesHandler_ErrorSynchingExperiment,exp.getName()),e);
          TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_Error + CR + CR+ e.getMessage());
        }
      }
    }
;
    thread.start();
  }
 else {
    TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_WrongTraceNumber);
  }
  return null;
}

Fixed version (ground truth):
@Override public Object execute(ExecutionEvent event) throws ExecutionException {
  IWorkbenchWindow window=PlatformUI.getWorkbench().getActiveWorkbenchWindow();
  if (window == null) {
    return null;
  }
  IWorkbenchPage page=PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
  IWorkbenchPart part=page.getActivePart();
  if (part == null) {
    return Boolean.FALSE;
  }
  ISelectionProvider selectionProvider=part.getSite().getSelectionProvider();
  if (selectionProvider == null) {
    return Boolean.FALSE;
  }
  ISelection selection=selectionProvider.getSelection();
  fSelection=null;
  final ArrayList<TmfTraceElement> tl=new ArrayList<>();
  final ArrayList<TmfExperimentElement> uiexperiment=new ArrayList<>();
  if (selection instanceof TreeSelection) {
    fSelection=(TreeSelection)selection;
    Iterator<Object> iterator=fSelection.iterator();
    while (iterator.hasNext()) {
      Object element=iterator.next();
      if (element instanceof TmfTraceElement) {
        tl.add((TmfTraceElement)element);
      }
 else       if (element instanceof TmfExperimentElement) {
        TmfExperimentElement exp=(TmfExperimentElement)element;
        uiexperiment.add(exp);
        for (        TmfTraceElement trace : exp.getTraces()) {
          tl.add(trace);
        }
      }
    }
  }
  if ((uiexperiment.size() != 1) || (tl.size() < 2)) {
    TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_WrongTraceNumber);
    return null;
  }
  Thread thread=new Thread(){
    @Override public void run(){
      final ITmfTrace[] traces=new ITmfTrace[tl.size()];
      final TmfExperimentElement exp=uiexperiment.get(0);
      for (int i=0; i < tl.size(); i++) {
        ITmfTrace trace=tl.get(i).instantiateTrace();
        ITmfEvent traceEvent=tl.get(i).instantiateEvent();
        if (trace == null) {
          TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_WrongType + tl.get(i).getName());
          for (int j=0; j < i; j++) {
            traces[j].dispose();
          }
          return;
        }
        try {
          trace.initTrace(tl.get(i).getResource(),tl.get(i).getLocation().getPath(),traceEvent.getClass());
          TmfTraceManager.refreshSupplementaryFiles(trace);
        }
 catch (        TmfTraceException e) {
          TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_InitError + CR + CR+ e);
          trace.dispose();
          for (int j=0; j < i; j++) {
            traces[j].dispose();
          }
          return;
        }
        traces[i]=trace;
      }
      exp.refreshSupplementaryFolder();
      final TmfExperiment experiment=new TmfExperiment(ITmfEvent.class,exp.getName(),traces,exp.getResource());
      try {
        final SynchronizationAlgorithm syncAlgo=experiment.synchronizeTraces(true);
        TmfTraceManager.refreshSupplementaryFiles(experiment);
        Display.getDefault().asyncExec(new Runnable(){
          @Override public void run(){
            List<TmfTraceElement> tracesToAdd=new ArrayList<>();
            List<TmfTraceElement> tracesToRemove=new ArrayList<>();
            for (            TmfTraceElement traceel : tl) {
              ITmfTrace expTrace=null;
              for (              ITmfTrace t : experiment.getTraces()) {
                if (t.getResource().equals(traceel.getResource())) {
                  expTrace=t;
                  break;
                }
              }
              if ((expTrace != null) && syncAlgo.isTraceSynced(expTrace.getHostId())) {
                TmfTraceElement origtrace=traceel.getElementUnderTraceFolder();
                String newname=traceel.getName();
                IContainer parentFolder=origtrace.getResource().getParent();
                boolean traceexists;
                do {
                  traceexists=false;
                  newname+="String_Node_Str";
                  if (parentFolder.findMember(newname) != null) {
                    traceexists=true;
                  }
                }
 while (traceexists);
                TmfTraceElement newtrace=origtrace.copy(newname);
                if (newtrace == null) {
                  TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_Error + CR + CR+ String.format(Messages.SynchronizeTracesHandler_CopyProblem,origtrace.getName()));
                  continue;
                }
                ITmfTrace trace=newtrace.instantiateTrace();
                ITmfEvent traceEvent=newtrace.instantiateEvent();
                try {
                  trace.initTrace(newtrace.getResource(),newtrace.getLocation().getPath(),traceEvent.getClass());
                }
 catch (                TmfTraceException e) {
                  Activator.getDefault().logError(String.format(Messages.SynchronizeTracesHandler_ErrorSynchingForTrace,exp.getName(),traceel.getName()),e);
                  TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_Error + CR + CR+ e.getMessage());
                }
                trace.setTimestampTransform(syncAlgo.getTimestampTransform(trace));
                TmfTraceManager.refreshSupplementaryFiles(trace);
                trace.dispose();
                tracesToAdd.add(newtrace);
                tracesToRemove.add(traceel);
              }
            }
            experiment.dispose();
            IFolder tmpFolder=exp.getTraceSupplementaryFolder("String_Node_Str");
            IResource syncFile=null;
            for (            IResource resource : exp.getSupplementaryResources()) {
              if (resource.getName().equals(TmfExperiment.SYNCHRONIZATION_FILE_NAME)) {
                try {
                  resource.move(tmpFolder.getFile(exp.getName() + '.' + TmfExperiment.SYNCHRONIZATION_FILE_NAME).getFullPath(),false,null);
                  syncFile=resource;
                  break;
                }
 catch (                CoreException e) {
                  Activator.getDefault().logError(String.format(Messages.SynchronizeTracesHandler_ErrorSynchingExperiment,exp.getName()),e);
                }
              }
            }
            for (            TmfTraceElement trace : tracesToRemove) {
              try {
                exp.removeTrace(trace);
              }
 catch (              CoreException e) {
                Activator.getDefault().logError(String.format(Messages.SynchronizeTracesHandler_ErrorSynchingForTrace,exp.getName(),trace.getName()),e);
                TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_Error + CR + CR+ e.getMessage());
              }
            }
            for (            TmfTraceElement trace : tracesToAdd) {
              exp.addTrace(trace);
            }
            IResource resource=tmpFolder.getFile(exp.getName() + '.' + TmfExperiment.SYNCHRONIZATION_FILE_NAME);
            if (resource.exists() && syncFile != null) {
              try {
                resource.move(syncFile.getFullPath(),false,null);
              }
 catch (              CoreException e) {
                Activator.getDefault().logError(String.format(Messages.SynchronizeTracesHandler_ErrorSynchingExperiment,exp.getName()),e);
              }
            }
          }
        }
);
      }
 catch (      TmfTraceException e) {
        Activator.getDefault().logError(String.format(Messages.SynchronizeTracesHandler_ErrorSynchingExperiment,exp.getName()),e);
        TraceUtils.displayErrorMsg(Messages.SynchronizeTracesHandler_Title,Messages.SynchronizeTracesHandler_Error + CR + CR+ e.getMessage());
      }
    }
  }
;
  thread.start();
  return null;
}