private void checkExtension(MavenVersionAwareSupportExtension extension) {
    if (extension == null) {
      if (StringUtil.compareVersionNumbers(myDistribution.getVersion(), "3") < 0) {
        throw new BuildIssueException(new InstallMaven2BuildIssue());
      }
      throw new IllegalStateException("Maven distribution at" + myDistribution.getMavenHome().toAbsolutePath() + " is not supported");
    }
    MavenLog.LOG.info("Using extension " + extension + " to start MavenServer");
  }
private void checkExtension(MavenVersionAwareSupportExtension extension)