The rule "Design for extension" has been removed from the default profiles. Number of violations can decrease on projects using these profiles. See SONAR-2275.
Analysis will fail if the package name defined in Java files does not match the physical directory. For example the package "org.foo.bar" must be defined in the directory "org/foo/bar". Oracle Java compiler is permissive and does not check this condition. See SONAR-2348.