修改设置
- Press Ctrl+Shift+A
 - Enter “unused declar”
 - Double-click on “Unused declaration”
 - Settings will pop up
 
设置
- Click on Java/Declaration redundancy/Unused declaration
 - on the right bottom select “On the fly editor settings”
 - untick check fields, …, check parameters. Only Check Classes should be ticked.
 - Press OK
 
Settings closes
- On the menu bar, click on Analyze / Run Inspection by Name (or Ctrl+Alt+Shift+I)
 - Insert text “Unused decla”
 - 
    
Select “Unused declaration Java Declaration redundancy”  - Search starts
 
Check the job state on bottom of Idea, when finished: enjoy the results and the great feeling of cleaning up the messed code. :)