Checkstyle vs. PMD

Question

We are introducing static analysis tools into the build system for our Java product. We are using Maven2 so Checkstyle and PMD integration come for free. However it looks like there is a large overlap in functionality between these two tools, in terms of enforcing basic style rules.

Is there a benefit from utilizing both of these? I don't want to maintain 2 tools if one will work. If we choose one, which one should we use and why?

We are also planning on using FindBugs. Are there other static analysis tools we should look at?

Update: Consensus seems to be that PMD is preferred over CheckStyle. I don't see a solid reason to use both, and I don't want to maintain 2 sets of rule files, so we will probably aim for PMD exclusively. We'll also be bringing in FindBugs, and perhaps, eventually, Macker to enforce architectural rules.

Answer 1

PMD is what I find more people referring to. Checkstyle was what people were referring to 4 years ago but I believe PMD is maintained more continuously and what other IDEs/plugins choose to work with.

Answer 2

You should definitely use FindBugs. In my experience, the false-positive rate is very low, and even the least-critical warnings it reports are worth addressing to some extent.

As for Checkstyle vs. PMD, I would not use Checkstyle since it is pretty much only concerned with style. In my experience, Checkstyle will report on a ton of things that are completely irrelevant. PMD on the other hand is also able to point out questionable coding practices and its output is generally more relevant and useful.

Answer 3

I would echo the comment that PMD is the more current product for Java style/convention checking. With respect to FindBugs, many commercial development groups are using Coverity.

Answer 4

Hello, Both softwares are useful. Checkstyle will help you during your programming by checking your coding style i.e braces, naming etc. Simple things but very numerous!

PMD will help you by checking more complicate rules like during the design of your classes, or for more special problems like implementing correctly the clone function. Simply, PMD will check your programming style

However, both softwares suffers from similar rules sometimes bad explained. With a bad configuration, you may check things twice or two opposite things i.e "Remove useless constructors" and "Always one constructor".

Cheers, SL.

Answer 5

We use both:

• Checkstyle to make sure that everyone in the team write code in a similar maner
• PMD to find problematic code areas and next refactoring targets

Answer 6

I find Checkstyle and PMD are best for enforcing style issues and simple obvious coding bugs. Although I've found that I like using Eclipse and all the warnings it provides better for that purpose. We enforce stuff by using shared preferences and marking them as actual errors. That way, they never get checked in in the first place.

What I would strongly and enthusiastically recommend is using FindBugs. Because it works at the bytecode level it can check things that are impossible at the source level. While it spits out its fair share of junks, it has found many actual and important bugs in our code.

Answer 7

Both tools are configurable and can do just about the same things. That said, if we're talking about out-of-the-box stuff, there is a great deal of overlap, but there are distinct rules/checks as well. For example, Checkstyle has stronger support for checking Javadoc and finding magic numbers, to name a couple. Additionally, Checkstyle has an "import control" feature that looks similar to the functionality of Macker (I've not used Macker).

If there are things that are important to you that Checkstyle does out-of-the-box that PMD doesn't, you might consider a minimal Checkstyle configuration with only those checks. Then institute a policy that the Checkstyle configuration cannot grow, simply remove checks as you implement similar functionality with, say, custom PMD rules.

Also consider that if you decide that the Checkstyle "import control" feature covers what you wanted from Macker, then you could implement PMD/Checkstyle instead of PMD/Macker. Either way it's two tools, but with Checkstyle, you'd get the stuff that PMD doesn't do out-of-the-box "for free."

Answer 8

Checkstyle and PMD both are good at checking coding standards and are easy to extend. But PMD has additional rules to check for cyclomatic complexity,Npath complexity,etc which allows you write healthy code.

Another advantage of using PMD is CPD (Copy/Paste Detector).It finds out code duplication across projects and is not constrained to JAVA.It works for JSP too. Neal Ford has a good presentation on Metrics Driven Agile Development that talks about many tools that are helpful for Java/JEE Development

Answer 9

PMD is the finest tool when compare with checkstyles. Checkstyles may not have the capability to analyse the code while PMD offering many features to do so! Offcourse PMD has not released rules for javadoc, comments, indentations and etc. And by the way i am planning to implement these rules.......thanx