Find start node of loop in linkedlist in java

public Node findStartNodeOfTheLoop() {
	Node fastPtr = head;
	Node slowPtr = head;
	boolean loopExists=false;
	while (fastPtr != null && fastPtr.next != null) {
		fastPtr = fastPtr.next.next;
		slowPtr = slowPtr.next;
		if (slowPtr == fastPtr)
		{
			loopExists=true;
			break;
		}
 
	}
	if(loopExists)
	{
		slowPtr=head;
 
		while(slowPtr!=fastPtr)
		{
			slowPtr=slowPtr.next;
			fastPtr=fastPtr.next;
		}
 
 
	}
	else
	{
		System.out.println("Loop does not exists");
		slowPtr=null;
	}
	return slowPtr;
}