WARNING: This blog entry was imported from my old blog on blogs.sun.com (which used different blogging software), so formatting and links may not be correct.
A while ago I argued that you should completely avoid Tab characters in your Java source files. Use spaces for indentation. I won't repeat those arguments here. But even those arguing in favor of tab-indented source files agree that mixing spaces and tabs is evil.
The problem is that sometimes you're not aware that you're working on source with mixed tabs and spaces. This can happen easily if you edit the source files with an editor that has the wrong (as far as you're concerned) handling of Tabs.
To help avoid this you can use a simple NetBeans module I just committed into CVS, under
contrib/fixtabs. You can grab the NBM file here and install via Tools | Update Center. I'll submit it to nbextras.org soon so you can get it there later.
Here's what the module looks like in action. If you for example open the JDK
JTable class and look at the constructor, you'll see something like this (click for full size):
When you encounter files like this, you can go to the edit menu and select the action to convert the tabs to spaces. You can also turn off Tab highlighting here.
(Update 4/28/06: I changed this such that the "checkbox" toggle is now in the View menu, along with other view states you can enable and disable, and I moved the Convert action to the Source menu along with other source transformation actions.)
The module is similar to one of my favorite modules (which I guess I haven't described yet) - the "stripwhitespace" module. That module highlights trailing whitespace in the current source file, and lets you remove these. Not only is the fixtabs module similar - it's heavily based on the same source code.
Let me know if you encounter any bugs.