private void display(){
		//display data
		Node currentNode=firstNode;
		while(currentNode!=null){
			Class<?> c = currentNode.getData().getClass();
			
			
			try {
				Object instance = c.newInstance();
				System.out.println(new Integer((Integer) (currentNode.getData())));
				currentNode=currentNode.getNext();
			} catch (InstantiationException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (IllegalAccessException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

		}
	}