protected @Nullable Path getSystemDefaultJavaHome() {
    String homePath = null;
    if (new File(JAVA_HOME_FIND_UTIL).canExecute()) {
      homePath = ExecUtil.execAndReadLine(new GeneralCommandLine(JAVA_HOME_FIND_UTIL));
    }
    if (homePath != null) {
      return Paths.get(homePath);
    }
    return null;
  }
protected @Nullable Path getSystemDefaultJavaHome()