Binary Tree Queue

public class BinaryTreeQueue{
        private class BTQNode{
            public BTQNode(BinaryTree bt){
                this.content = bt;
            }
            public BTQNode next;
            public BinaryTree content;

            public void setNext(BTQNode next){this.next = next;}
        }
        BTQNode start;

        public void insert(BinaryTree bt){
            BTQNode current = start;
            if(start == null) start = new BTQNode(bt);
            else {
                while(current.next !=null) current = current.next;
                current.next = new BTQNode(bt);
            }
        }

        public BinaryTree pull(){
            BTQNode temp = start;
            if(start.next != null) start = start.next;
            return temp.content;
        }
    }
}