e.printStackTrace();
if(log.isErrorEnabled()) { log.error("Exception", e); }
  public int addElement(Transferable transferable, DefaultMutableTreeNode target,                        DefaultMutableTreeNode before)  {    Object data = null;    try {      data = transferable.getTransferData(transferable.getTransferDataFlavors()[0]);    } catch (Exception e) {      e.printStackTrace();      return DnDConstants.ACTION_NONE;    }    if (data instanceof DMTNArray) {      DMTNArray nodes = (DMTNArray) data;      for (int i = 0; i < nodes.nodes.length; i++) {        addElement(nodes.nodes[i], target, before);      }    } else {      addElement((DefaultMutableTreeNode) data, target, before);    }    return DnDConstants.ACTION_MOVE;  }