Program: 69939
Project: 69939
Buggy source:
public void run(){
  if (Policy.TRACING_ACTIONS) {
    System.out.println("String_Node_Str");
  }
  List existingDataSets=getDataSets();
  if (existingDataSets.isEmpty()) {
    MessageDialog.openError(PlatformUI.getWorkbench().getDisplay().getActiveShell(),Messages.getString("String_Node_Str"),Messages.getString("String_Node_Str"));
    notifyResult(false);
  }
 else {
    HandleAdapterFactory.getInstance().getReportDesignHandleAdapter().getModuleHandle().getCommandStack().startPersistentTrans(Messages.getString("String_Node_Str"));
    JointDataSetWizard wizard=new JointDataSetWizard();
    wizard.setWindowTitle(Messages.getString("String_Node_Str"));
    WizardDialog dialog=new WizardDialog(PlatformUI.getWorkbench().getDisplay().getActiveShell(),wizard){
      protected void configureShell(      Shell newShell){
        super.configureShell(newShell);
        newShell.setSize(750,650);
        Rectangle rect=Display.getDefault().getBounds();
        newShell.setLocation((rect.width - 750) / 2,(rect.height - 650) / 2);
      }
    }
;
    if (dialog.open() == WizardDialog.OK) {
      List newDataSets=getDataSets();
      editDataSet(existingDataSets,newDataSets);
      HandleAdapterFactory.getInstance().getReportDesignHandleAdapter().getModuleHandle().getCommandStack().commit();
      ReportRequest request=new ReportRequest(ReportRequest.CREATE_ELEMENT);
      List selectionObjects=new ArrayList();
      selectionObjects.add(dataSetHandle);
      request.setSelectionObject(selectionObjects);
      SessionHandleAdapter.getInstance().getMediator().notifyRequest(request);
      notifyResult(true);
    }
 else {
      HandleAdapterFactory.getInstance().getReportDesignHandleAdapter().getModuleHandle().getCommandStack().rollback();
      notifyResult(false);
    }
  }
}

Fixed version (ground truth):
public void run(){
  if (Policy.TRACING_ACTIONS) {
    System.out.println("String_Node_Str");
  }
  if (SessionHandleAdapter.getInstance().getReportDesignHandle() == null) {
    return;
  }
  List existingDataSets=getDataSets();
  if (existingDataSets.isEmpty()) {
    MessageDialog.openError(PlatformUI.getWorkbench().getDisplay().getActiveShell(),Messages.getString("String_Node_Str"),Messages.getString("String_Node_Str"));
    notifyResult(false);
  }
 else {
    if (SessionHandleAdapter.getInstance().getReportDesignHandle() == null) {
      return;
    }
    HandleAdapterFactory.getInstance().getReportDesignHandleAdapter().getModuleHandle().getCommandStack().startPersistentTrans(Messages.getString("String_Node_Str"));
    JointDataSetWizard wizard=new JointDataSetWizard();
    wizard.setWindowTitle(Messages.getString("String_Node_Str"));
    WizardDialog dialog=new WizardDialog(PlatformUI.getWorkbench().getDisplay().getActiveShell(),wizard){
      protected void configureShell(      Shell newShell){
        super.configureShell(newShell);
        newShell.setSize(750,650);
        Rectangle rect=Display.getDefault().getBounds();
        newShell.setLocation((rect.width - 750) / 2,(rect.height - 650) / 2);
      }
    }
;
    if (dialog.open() == WizardDialog.OK) {
      List newDataSets=getDataSets();
      editDataSet(existingDataSets,newDataSets);
      HandleAdapterFactory.getInstance().getReportDesignHandleAdapter().getModuleHandle().getCommandStack().commit();
      ReportRequest request=new ReportRequest(ReportRequest.CREATE_ELEMENT);
      List selectionObjects=new ArrayList();
      selectionObjects.add(dataSetHandle);
      request.setSelectionObject(selectionObjects);
      SessionHandleAdapter.getInstance().getMediator().notifyRequest(request);
      notifyResult(true);
    }
 else {
      HandleAdapterFactory.getInstance().getReportDesignHandleAdapter().getModuleHandle().getCommandStack().rollback();
      notifyResult(false);
    }
  }
}