Code style
To follow the proper coding style for this class, you should have IntelliJ insert spaces for indentation instead of tabs. This ensures that the code looks the same in every editor, regardless of the tab width settings. To do so, follow these instructions:
In IntelliJ, click on File then choose New Project Setup then Settings for New Projects.
In the navigation pane on the left side drill down to Editor > Code Style > Java.
In the Tabs and Indents submenu, ensure the Use tab character is unchecked. Underneath that, set the Tab size, Indent, and Continuation indent to 2.
Navigate to the Wrapping and Braces submenu, select Hard wrap at: and set to 100.
Click Apply and then OK. Please note if you wanted to ever go back to Default IDE schemes, you can select Default from the dropdown menu in Editor > Code Style > Java.
Now, in that navigation pane on the left side drill down to Editor > Inspections > Java > Code Style.
Scroll down through the options and ensure that Instance field access not qualified with this and Instance method call not qualified with this are ticked.
Hit Apply and Ok.
Finally, back at the top level menu, under Edit then Convert Indents, select To Spaces. Your IntelliJ IDEA environment should now reflect the desired coding style guidelines.