title: Why do we add an _ (underscore) before a variable name?
body: <p>Why do we add an _ (underscore) before a variable name in Java while variable declaration?</p>
  <p>I have tried on Google Search, but I actually couldn't find the exact answer for it.</p>
  <p>Is it just a type of declaration as the user wants or is there any proper mechanism and reason to do so?</p>