Program: 148674
Project: 148674
Buggy source:
private boolean dropTargetValidate(DropTargetEvent event){
  if (event.item == null)   return false;
  Object obj=event.item.getData();
  if (obj instanceof TreeObject) {
    TreeObject treeObj=(TreeObject)obj;
    if (treeObj.getParent() == null)     System.out.println(treeObj.getDisplayName());
    int xtentisType=LocalTreeObjectRepository.getInstance().receiveUnCertainTreeObjectType(treeObj);
    if ((treeObj.getType() != dragType && treeObj.getType() != TreeObject.CATEGORY_FOLDER) || dragType == TreeObject.CATEGORY_FOLDER || dragType == TreeObject.DATA_MODEL_RESOURCE || dragType == TreeObject.DATA_MODEL_TYPES_RESOURCE || dragType == TreeObject.CUSTOM_TYPES_RESOURCE || dragType == TreeObject.PICTURES_RESOURCE || (treeObj.getType() == TreeObject.CATEGORY_FOLDER && xtentisType != dragType && !(dragType == TreeObject.JOB || dragType == TreeObject.WORKFLOW_PROCESS)) || (treeObj.getType() == TreeObject.CATEGORY_FOLDER && treeObj.getParent().getType() == dragType && treeObj.getDisplayName().equals("String_Node_Str")) || (LocalTreeObjectRepository.getInstance().isInSystemCatalog(treeObj.getParent()))) {
      event.detail=DND.DROP_NONE;
    }
 else {
      for (      TreeObject tos : dndTreeObjs) {
        if (tos == obj) {
          event.detail=DND.DROP_LINK;
          break;
        }
 else {
          if (tos.getParent().getType() == TreeObject.CATEGORY_FOLDER && tos.getParent().getDisplayName().equals("String_Node_Str")) {
            event.detail=DND.DROP_NONE;
          }
          event.detail=DND.DROP_MOVE;
        }
      }
    }
  }
  return event.detail != DND.DROP_NONE;
}

Fixed version (ground truth):
private boolean dropTargetValidate(DropTargetEvent event){
  if (event.item == null)   return false;
  Object obj=event.item.getData();
  if (obj instanceof TreeObject) {
    TreeObject treeObj=(TreeObject)obj;
    if (treeObj.getParent() == null)     System.out.println(treeObj.getDisplayName());
    int xtentisType=LocalTreeObjectRepository.getInstance().receiveUnCertainTreeObjectType(treeObj);
    if ((treeObj.getType() != dragType && treeObj.getType() != TreeObject.CATEGORY_FOLDER && !(dragType == TreeObject.JOB || dragType == TreeObject.WORKFLOW_PROCESS)) || dragType == TreeObject.CATEGORY_FOLDER || dragType == TreeObject.DATA_MODEL_RESOURCE || dragType == TreeObject.DATA_MODEL_TYPES_RESOURCE || dragType == TreeObject.CUSTOM_TYPES_RESOURCE || dragType == TreeObject.PICTURES_RESOURCE || (treeObj.getType() == TreeObject.CATEGORY_FOLDER && xtentisType != dragType && !(dragType == TreeObject.JOB || dragType == TreeObject.WORKFLOW_PROCESS)) || (treeObj.getType() == TreeObject.CATEGORY_FOLDER && treeObj.getParent().getType() == dragType && treeObj.getDisplayName().equals("String_Node_Str")) || (LocalTreeObjectRepository.getInstance().isInSystemCatalog(treeObj.getParent()))) {
      event.detail=DND.DROP_NONE;
    }
 else {
      for (      TreeObject tos : dndTreeObjs) {
        if (tos == obj) {
          event.detail=DND.DROP_LINK;
          break;
        }
 else {
          if (tos.getParent().getType() == TreeObject.CATEGORY_FOLDER && tos.getParent().getDisplayName().equals("String_Node_Str")) {
            event.detail=DND.DROP_NONE;
          }
          event.detail=DND.DROP_MOVE;
        }
      }
    }
  }
  return event.detail != DND.DROP_NONE;
}