public String getMessage() {
    StringBuffer sb = new StringBuffer(40);
    sb.append(super.getMessage());
    if (m_key != null | m_group != null) {
      sb.append(": ");
      if (m_group != null) {
        sb.append("group = ").append(m_group);
        if (m_key != null) {
          sb.append(", ");
        }
      }
      if (m_key != null) {
        sb.append("key = ").append(m_key);
      }
    }
    return sb.toString();
  }