title: Convert middle substring to "*"
body: <p>I have a string <code>String email="rachitgulati26@gmail.com"</code> so its length is 24.</p>
  
  <p>I want result like rachit************il.com.That means 1/4 of initial same and last 1/4 same.</p>
  
  <p>Just want to convert 1/2 from middle to * with the help of regEX.</p>
  
  <p>Thanks</p>