Intellij Idea - automatically add final keyword to the generated variables

Go to preferences -> Code Style -> Code Generation and enable "Make generated local variables final" in the "Final modifier" section. You can also try searching for "final" in preferences.

For Windows User;

Go to File -> Settings -> Editor -> Code Style -> Select Preferred Language (Java) -> Checkbox -> Make generated local variables final, Make generated parameters final -> Apply -> OK

In IntelliJ 14.1.3

1. Preferences > Editor > Code Style > Java
2. To the far right ,there's a tab called Code Generation
3. In the section called Final Modifier there are two choices:
   • Make generated local variables final
   • Make generated parameters final

After selecting "introduce local variable" there is a little gear to the right of the variable name. Click that and check "Declare final". That variable will be marked as final and Intellij will remember your preference until changed.