If you use Eclipse for day to day Java development take a deep breath and relax. You are neither the first nor the only one. In fact, you are part of a growing community of Java developers in the world. SD Times recently reported that two-thirds of the enterprise software developers—66.3 percent—use Eclipse. This adoption rate is a success for an open source project, albeit supported by a giant like IBM.

The agile developers know that at the end it’s often not the tool that makes the difference. It’s the fundamental engineering practices. When the discussion goes beyond the tools it suddenly opens so many possibilities that even the most staunch tools proponents/opponents can sit down and unite in a common strategy. Let’s take coding standards for example. We all know that there are tons of tools for static code analysis and early defect detection. The Agile teams have choices in this matter. They can implement a set of static code analysis as part of their Continuous Integration (CI) cycle and get great reports the instant a potential bug gets checked-in. They can also encourage individual developers to use Eclipse plugins for code analysis and perform the same checks before they commit the code.

Two major plugins for code analysis in Eclipse are PMD and Checkstyle. Of course, Eclipse itself is also catching-up and it is constantly increasing its own set of code style checks. A look at Window | Preferences | Java | Compiler | Errors/Warnings reveals that the number and depth of the built-in code checks is fairly substantial.

Nevertheless, in this blog entry I would like to show you a quick example of how to setup and use Checkstyle for Eclipse .

Despite the fact that I use PMD and Checkstyle (and others for that matter, like Findbugs) in my daily projects, I favor Checkstyle for the following reasons:

• The integration of the tool to the environment seems to be tighter
• The rule customization and management in Checkstyle is way easier than PMD. I like!
• Checkstyle provides a few nifty features such as a pie chart depicting the distribution of problems
• Checkstyle comes with a richer set of predefined rules
• Better website documentation and easier learning curve

All and all Checkstyle makes my life easier, and especially after configuring a set of rules that make the sense for the project environment, it’s a workhorse! An added benefit of the custom rulesets is that they can be checked into the code repository, shared among the development team and reused in the CI static analysis phase. The latter can be achieved through integrating tools such as CruiseControl, Maven and Ant with the respective Checkstyle plugins. This brings a unified coding standard to the entire development team.

Quick Tutorial

1. Download and start Eclipse 3.2
2. Navigate to Help | Software Updates | Find and Install
3. Select Search for new features to install
4. Add a new remote site Checkstyle and point it to http://eclipse-cs.sourceforge.net/update
5. Finish the wizard and restart Eclipse
6. Create a new Java project, checkmeup
7. Add the following Java class:

   public class CheckMeUp {
      public void thisMethodShouldHaveAShorterAndCoolerName(String WHYALLCAPS, int g) {
         if (true) {
         }
         else {
         }
   
         while (true) {
            String x = "The white fox jumped over the red rabbit, which in turn jumped over my yellow submarine.";
            String y = x + "...";
         }
      }
   }
   

8. Build the project
9. In the Package explorer right-click on checkmeup and select Properties | Checkstyle
10. Check Checkstyle active for this project and select Sun Checks (Eclipse) - (Global) as the ruleset
11. Navigate to Window | Show view | Other…
12. Select Checkstyle | Checkstyle violations
13. Notice the 27 violations in this simple Java class
14. Now, let’s play with the rules. Assume that you do not like the Line contains a tab character rule. The sample class has 12 of it. Navigate to Window | Preferences | Checkstyle and Click on New…
15. Select Internal Configuration, enter a name and description. Click Import… and navigate to ECLIPSE_HOME/plugins/com.atlassw.tools.eclipse.checkstyle_x.x.x and select sun_checks_eclipse.xml. This will import all Sun Eclipse rules for the new custom ruleset. Also note that Checkstyle will create a new custom ruleset xml file under WORKSPACE/.metadata/.plugins/com.atlassw.tools.eclipse.checkstyle/internal_config__xxxxxxxxxxx.xml. This file can be added into the code repository and shared among the development team. Click OK.
16. Double click the new ruleset. Click Whitespace and uncheck the Tab Character rule
17. Back in the project properties, select the new custom rule as your configuration
18. Click OK. The tab warnings are gone.
19. In the Checkstyle violations view click the chart icon in the upper right corner. This will open the pie chart view shown below

    

20. Enjoy.