Quality of source code can be examined by many different tools, Checkstyle is one of them, but not the only one. Source code of such tools need to be checked also. Checkstyle uses its own tool to check its sources. But there is no limit to perfection and we can make Checkstyle source code even better than it is now. The idea is to reuse and configure some other well-known static code analysers (PMD, Sonar, Eclipse, IntelliJ IDEA Inspection, Huntbugs, Pitest) to run all checks on Checkstyle main and source code at each pull request.