You CANNOT upgrade automatically to 2.4
Version 2.4 moves Java from being an "ecosystem" of multiple plugins to a single, stand-along
alone plugin that encompasses most of the functionality formerly contained in the ecosystem. Specifically,
Unfortunately, SonarQube's update center cannot handle the switch gracefully. You may use the update center to download the new version of the plugin. However, you must manually remove the Surefire, JaCoCo, and Squid for Java plugins from$SONARQUBE_HOME/extensions/plugins.
If you want to see a live example of the capabilities of the Java Ecosystem, you can have a look at SonarQube on SonarQube.
Analysing a Java project without providing the Java bytecode of the source files and of all the project dependencies (jar files) is possible but will lead to highly decrease the number of issues found by the analyzer (false-negatives). Moreover the detection of cycles between packages and the display of the DSM will be automatically deactivated. As soon as a class required to efficiently do an analysis is missing a warning like the following one is logged :
[WARN] [08:40:21.769] Class 'XXXXXX' is not accessible through the ClassLoader.
- Java FAQ
- Metric definitions
- Many additional plugins are available
- Extending Coding Rules. To navigate the Abstract Syntax Tree (AST) and implement XPath rules, download the SSLR Java Toolkit.