To follow the proper coding style for this class, you should have Eclipse 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 Eclipse, select Preferences in the Window menu.
In the navigation pane on the left side of the Preferences dialog, drill down to Java > Code Style > Formatter.
Under Tab policy, select Spaces only.
Rename the profile to something like Mine and click OK.
Back in the main Preferences dialog, in the navigation pane on the left side, drill down to General > Editors > Text Editors, and check "Show line numbers".
Select OK to close the dialog.