title: Why do we need to use toString method with stringbuilder
body: <p>Here what is the difference between line 6 and line 8? They both print the same string.Why do we need to use toString with StringBuilder.    </p>
  
  <pre><code>     StringBuilder s = new StringBuilder("hello");//line1
       System.out.println(s);//line2
       s.append("hi");//line3
       System.out.println(s);
       s.append("okk");
       System.out.println(s);//line 6
       s.toString();
       System.out.println(s);//line 8
  </code></pre>