class LinkedList implements
    Externalizable {

    public T removeFirst() {
        if ( this.firstNode == null ) {
            return null;
        }
        final T node = this.firstNode;
        this.firstNode = node.getNext();
        node.setNext( null );
        if ( this.firstNode != null ) {
            this.firstNode.setPrevious( null );
        } else {
            this.lastNode = null;
        }
        this.size--;
        return node;
    }

    public  LinkedList();
    public  LinkedList(final T node);

}