Remove duplicates from unsorted linked list in scala

Scala program for Remove duplicates from unsorted linked list. Here problem description and explanation.

// Scala Program to 
// Delete duplicate nodes in unsorted linked list
class LinkNode(var data: Int,
	var next: LinkNode)
{
	def this(data: Int)
	{
		this(data, null);
	}
}
class LinkedList(var head: LinkNode,
	var tail: LinkNode)
{
	// Class constructors
	def this()
	{
		this(null, null);
	}
	// Insert new element at end position
	def insert(value: Int): Unit = {
		// Create new node
		var node: LinkNode = new LinkNode(value);
		if (this.head == null)
		{
			// Add first node
			this.head = node;
		}
		else
		{
			// Add new node at the last position
			this.tail.next = node;
		}
		// Make new tail 
		this.tail = node;
	}
	// Display all node value
	def display(): Unit = {
		if (this.head != null)
		{
			print("Linked List Element :");
			var temp: LinkNode = this.head;
			while (temp != null)
			{
				// Display node value
				print("  " + temp.data);
				// Visit to next node
				temp = temp.next;
			}
		}
		else
		{
			println("Empty Linked list");
		}
	}
	def removeNode(): Unit = {
		if (this.head == null)
		{
			// When linked list empty
			print("Empty Linked list");
		}
		else
		{
			// Auxiliary variable
			var temp: LinkNode = this.head;
			var hold: LinkNode = null;
			var initial: LinkNode = null;
			var current: LinkNode = null;
			// Outer loop
			while (temp != null)
			{
				// New last node
				this.tail = temp;
				current = temp;
				initial = current.next;
				// Inner loop
				// Remove all node which value is similar to temp node
				while (initial != null)
				{
					if (temp.data == initial.data)
					{
						// Get remove node
						hold = initial;
					}
					else
					{
						current = initial;
					}
					// Visit to next node
					initial = initial.next;
					if (hold != null)
					{
						current.next = initial;
						// remove node
						hold = null;
					}
				}
				// Visit to next node
				temp = temp.next;
			}
		}
	}
}
object Main
{
	def main(args: Array[String]): Unit = {
		// new linked list
		var task: LinkedList = new LinkedList();
		// Add tested element
		task.insert(1);
		task.insert(2);
		task.insert(9);
		task.insert(4);
		task.insert(9);
		task.insert(3);
		task.insert(1);
		task.insert(7);
		task.insert(2);
		task.insert(1);
		println("\nBefore Delete ");
		task.display();
		task.removeNode();
		println("\nAfter Delete ");
		task.display();
	}
}

Output

Before Delete
Linked List Element :  1  2  9  4  9  3  1  7  2  1
After Delete
Linked List Element :  1  2  9  4  3  7