Node class and LinkeList class

gistfile1.txt

package ds.SinglyLinkedList;

public class Node {
	public int data;
	public Node next;
	
	public displayNode() {
		System.out.println("{ "+ data + " }");
		
	}

}

//End of Node class
//Start of LinkedList class

package ds.SinglyLinkedList;

public class SinglyLinkedList {
	private Node first;
	
	
	public singlyLinkedList() {
		
	}
	
	public boolean isEmpty() {
		return (first == null);
		
	}
	
	//used to insert at the beginning of the list
	public void insertFirst(int data) {
		Node newNode = new Node();
		newNode.data = data;
		newNode.next = first;
		first = newNode;
	}
	
	public Node deleteFirst() {
		Node temp = first;
		first = first.next;
		return temp;
	}
	
	public void displayList() {
		System.out.println("List (first --> last");
		Node current = first;
		while(current != null) {
			current.displayNode();
			current = current.next;
		}
		System.out.println();
	}

}