public class Node {

    // When ever a new node is created the address will be null by default

    public int data;    // Data Field
    public Node next;   // Address Field

    // Constructor is to create the new node
    public Node(int data) {
        this.data = data; // set the data
        next = null;      // set the address to null by default
    }


}

public class InsertionInEndOfList {

    private CustLinkedList mList;

    public InsertionInEndOfList(CustLinkedList mList) {
        this.mList = mList;
    }

    public CustLinkedList push() {
        System.out.println("===============================================");
        System.out.println("Enter the element to insert");
        Scanner input = new Scanner(System.in);
        if(new UtilCheckInteger(input).checkIsInteger()) {
            int selection = input.nextInt();
            //Create the node
            Node mNode = new Node(selection);

            Node prevNode = mList.head;
            while(prevNode!=null) {
                prevNode = prevNode.next;
            }

            prevNode.next=mNode;

        } else {
            mList = new CreationOfList().initFunctionality();
        }

        return mList;
    }

}

prevNode.next=mNode;