Detect if there is Loop present in a Linkedlist

package linkedlist.singly;

public class DetectLoopInLinkList {

 Node startNode;
 public static void main(String[] args) {
  DetectLoopInLinkList g = new DetectLoopInLinkList();

  Node n1 = new Node(10);
  Node n2 = new Node(20);
  Node n3 = new Node(30);
  Node n4 = new Node(40);
  Node n5 = new Node(50);
  Node n6 = new Node(60);
  Node n7 = new Node(70);
  Node n8 = new Node(80);
  g.startNode = n1;

  n1.setNext(n2);
  n2.setNext(n3);
  n3.setNext(n4);
  n4.setNext(n5);
  n5.setNext(n6);
  n6.setNext(n7);
  n7.setNext(n8);
  n8.setNext(n4);

  System.out.println(g.isLoopPresent());
 }

 private boolean isLoopPresent(){
  Node str1=startNode, str2=startNode;
  while(str2!=null && str2.getNext()!=null){
   str1 = str1.getNext();
   str2 = str2.getNext().getNext();
   if(str1==str2)return true;
  }
  return false;
 }
}