Linked List using java which has insertion command

I created a linked list insertion program where i want to insert node when pressed 1 and exit when 0 is pressed but only first node i.e the head is being inserted not other nodes....
It seems like the first node is working fine but the other nodes are not inserted ..
Please help to identify where the problem lies.

import java.util.*;
// A simple Java program for traversal of a linked list 
public class LinkedList { 
Node head; // head of list which is object of Inner Node Class.. thus head.data is a valid statement..
/* Linked list Node.  This inner class is made static so that 
main() can access it */
static class Node { 
int data; 
Node next;
//Constructor
Node(int d) 
{ 
data = d; 
next = null; 
} // Constructor 
} 
/* This function prints contents of linked list starting from head */
public void printList() 
{ 
Node n = head; 
while (n != null) { 
System.out.print(n.data + " "); 
n = n.next; 
} 
} 
/* method to create a simple linked list with 3 nodes*/
public static void main(String[] args) 
{ 
Scanner sc=new Scanner(System.in);
int dt=0;
/* Start with the empty list. */
LinkedList llist = new LinkedList(); 
System.out.println("Enter 1 for entry 0 for exit");
int p = sc.nextInt();
while(p!=0)
{
if(llist.head==null)
{
System.out.println("Enter the first data in linked list");
dt=sc.nextInt();
llist.head = new Node(dt);
llist.head.next=null;
}
else     //problem is here// 
{  Node n=llist.head.next;
System.out.println("Enter the data in linked list");
dt=sc.nextInt();  
while (n != null)
{ 
Node nd = new Node(dt); 
nd.next = null;
}
}
System.out.println("Enter 1 for entry 0 for exit");    
p = sc.nextInt();    
}
llist.printList(); 
} 
}

In the while loop, you can keep looping while n.next is not null. This means that you will exit the loop when n.next is null, i.e. you reached the end of the list.

The else branch could be written like this:

LinkedList.Node n=llist.head;
System.out.println("Enter the data in linked list");
dt=sc.nextInt();
while (n.next != null)
{
n = n.next;
}
// if we reach here, n.next must be null, i.e. we have reached the end of the list
n.next = new LinkedList.Node(dt);

Alternatively, you could store the last node that was inserted in a variable. This way you don't need to find the end of the list every time.

LinkedList.Node tail = null;
while(p!=0)
{
if(llist.head==null)
{
System.out.println("Enter the first data in linked list");
dt=sc.nextInt();
llist.head = new LinkedList.Node(dt);
llist.head.next=null;
tail = llist.head;
} else {
System.out.println("Enter the data in linked list");
dt=sc.nextInt();
tail.next = new LinkedList.Node(dt);
tail = tail.next;
}
System.out.println("Enter 1 for entry 0 for exit");
p = sc.nextInt();
}

An even better way to do this would be to add an insert method to LinkedList:

public void insert(int data) {
if (head == null) {
head = new Node(data);
} else {
LinkedList.Node n = head;
while (n.next != null) {
n = n.next;
}
n.next = new Node(data);
}
}

Then the outer while loop can become:

while(p!=0)
{
System.out.println("Enter the data in linked list");
dt=sc.nextInt();
llist.insert(dt);
System.out.println("Enter 1 for entry 0 for exit");
p = sc.nextInt();
}