Ensuring code quality is an herculean task in J2EE/Java projects today. Fortunately,a lot of tools that help in improving the quality of the Java language code are available as free and open source software. Using these set tools make the code developed conformant to the standards right from the outset of the development phase.
Following is a one such list of usage of different tools to improve the Java code quality that I use in my projects:
1. IDE customization: This constitutes the first line of defense. All the developer IDE must be configured with the same rules for Java code and documentation. Be it Eclipse, Netbeans or Rational Application Developer. This ensures that the code is formatted in similar manner across IDEs and the entire code base is coherent. Further, the IDEs provide a 'Format' option that would automatically format the whole code to the specification provided. This step removes almost all developer 'coding standard' errors.
2.CheckStyle(http://checkstyle.sourceforge.net/): Checkstyle performs a detailed check of code conformance with Java Coding Standards. The tool also points out common functional errors made by programmers. A Checkstyle configuration file customized for the current project coding standards should be created and distributed to the team. This is a better way of communicating the project coding guidelines than a verbal discourse or a huge MS Word/PDF document.Checkstyle plug-ins are available for almost all the popular IDEs. The project Checkstyle configuration can be fed to the IDE plug-in so that any non-conformance is immediately highlighted to the developer in the code. This ensures the code developed is in line with the project coding standards.
3. FindBugs(http://findbugs.sourceforge.net/): FindBugs inspects the Java byte code for bug patterns. Running FindBugs on the code developed reveals a set of issues, majority of runtime bugs, that cannot be caught by the source code analysis tools. Again plug-ins are available for popular IDEs.
Note: Checkstyle and FindBugs can be used without an IDE. The IDE integration is a just an option and left to the discretion of the developer.
Once the above steps/tools have been performed on the code by the developer. The code is ready for the review phase.
Usage of such tools by developers, provide them with a lot of learning about the standards, do's and don'ts of Java programming. These tools free the reviewers from delving into code level laborious issues like documentation, indentation etc, which are best done with automated tools. The reviewer can use the same tools or tools like PMD(http://pmd.sourceforge.net/) and JNCSS(http://www.kclee.de/clemens/java/javancss/) to determine design issues, code complexity.etc.