Need help modifying this natural merge sort linked list algorithm in Java.

Please modify the algorithm below to take in a text file containing random integers, and write the sorted text to output.

For example, a text file containing the following integers:

1 2 48 99 33 100 299 300 4999 3928

// Java program to illustrate merge sorted

// of linkedList

public class linkedList

{

node head = null;

// node a,b;

static class node

{

int val;

node next;

public node(int val)

{

this.val = val;

}

}

node sortedMerge(node a, node b)

{

node result = null;

/* Base cases */

if (a == null)

return b;

if (b == null)

return a;

/* Pick either a or b, and recur */

if (a.val <= b.val)

{

result = a;

result.next = sortedMerge(a.next, b);

}

else

{

result = b;

result.next = sortedMerge(a, b.next);

}

return result;

}

node mergeSort(node h)

{

// Base case : if head is null

if (h == null || h.next == null)

{

return h;

}

// get the middle of the list

node middle = getMiddle(h);

node nextofmiddle = middle.next;

// set the next of middle node to null

middle.next = null;

// Apply mergeSort on left list

node left = mergeSort(h);

// Apply mergeSort on right list

node right = mergeSort(nextofmiddle);

// Merge the left and right lists

node sortedlist = sortedMerge(left, right);

return sortedlist;

}

// Utility function to get the middle of the linked list

node getMiddle(node h)

{

//Base case

if (h == null)

return h;

node fastptr = h.next;

node slowptr = h;

// Move fastptr by two and slow ptr by one

// Finally slowptr will point to middle node

while (fastptr != null)

{

fastptr = fastptr.next;

if(fastptr!=null)

{

slowptr = slowptr.next;

fastptr=fastptr.next;

}

}

return slowptr;

}

void push(int new_data)

{

/* allocate node */

node new_node = new node(new_data);

/* link the old list off the new node */

new_node.next = head;

/* move the head to point to the new node */

head = new_node;

}

// Utility function to print the linked list

void printList(node headref)

{

while (headref != null)

{

System.out.print(headref.val + " ");

headref = headref.next;

}

}

public static void main(String[] args)

{

linkedList li = new linkedList();

/*

* Let us create a unsorted linked lists to test the functions Created

* lists shall be a: 2->3->20->5->10->15

*/

li.push(15);

li.push(10);

li.push(5);

li.push(20);

li.push(3);

li.push(2);

System.out.println("Linked List without sorting is :");

li.printList(li.head);

// Apply merge Sort

li.head = li.mergeSort(li.head);

System.out.print(" Sorted Linked List is: ");

li.printList(li.head);

}

}