-- Frequently Asked (And Unasked) Questions --

If you feel there is a very obvious, essential question missing please drop us a note on the mailing list or enter a bug report.

I am getting error markers on all my files which saying:
Unable to get class information for XYZ
How to get rid of them?

If you are using RAD 6/7 or run Eclipse on IBMs J9 VM please read here.
In other cases modify your Checkstyle configuration file, setting the logLoadErrors property of the JavadocMethod and RedundantThrows check to true. You can do this via the plugins Configuration editor (recommended) or manually be adding the property to your Checkstyle configuration XML file(s).

I just dropped plug-in version x.x.x in Eclipse (replacing version z.z.z, which was working great) and I'm having some trouble using it.
When I go to Window > Preferences > Checkstyle an error occurs.
I looked into the Eclipse error log and found some NoClassDefFoundExceptions. Whats going on?

If you install the plug-in from the downloaded distributable (not via the Update Site) over an older version of the plug-in, Eclipse may have difficulties detecting the change and updating its cached information about the plug-in.
To force Eclipse to update this information you have to restart Eclipse with the -clean option.
For instance: <path-to-my-eclipse>\eclipse.exe -clean

I wrote a new Checkstyle rule. I know it works because I tested it. I created a .jar file with .class files and with messages.properties.
I can't plug-in my rule to Eclipse - i don't know how do it ?

It is now documented what to do to integrate custom checks with the plug-in. See here .

I use the Checkstyle Plug-in with my project which has only 1.000.000 source files.
Using Checkstyle on this project is extremely slow even after I upgraded to 4 GB memory!
What to do? (This question is a bit dramatized by the FAQ author)

Yes, checking such a project takes some time and memory resources.
You should try to decrease the number of files that are actually checked by using file sets and filter .