protected void removeAttribute(Object id){
  if (attributes != null) {
    attributes.remove(id);
    if (attributes.isEmpty()) {
      attributes=null;
    }
  }
}

protected void removeAttribute ( Object id ) { if ( attributes != null ) { attributes . remove ( id ) ; if ( attributes . isEmpty ( ) ) { attributes = null ; } } }
removes the specified attribute if it exist in this element this method allows creating a key that is non - string to be used by subclasses that optimize attributes retrieval
