sonar.java.source property to tell PMD which version of Java your source code complies to. The default value is 1.5. Possible values: 1.4, 1.5 or 5, 1.6 or 6, 1.7 or 7. Since version 2.2 of the plugin, this property can also be set to 1.8 or 8.
Rules on test
PMD tool provides some rules that can check the code of JUnit tests.Please note that these rules (and only these rules) will be applied only on the test files of your project.