title: eclipse why some codes in java files have background color before the file is edited
body: <p>As shown in the following picture, some java files have background color for code, and once edit the file, the color disappears. I would like to cancel this behavior. </p>
  
  <p><a href="https://i.stack.imgur.com/URUJB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/URUJB.png" alt="background color"></a></p>