有人可以解释一下HackerRank的代码吗？

class DoNotTerminate {

    public static class ExitTrappedException extends SecurityException {    
        private static final long serialVersionUID = 1;
    }

    public static void forbidExit() {
       final SecurityManager securityManager = new SecurityManager() {
           @Override
           public void checkPermission(Permission permission) {
              if (permission.getName().contains("exitvm")) {
                  throw new ExitTrappedException();
              }
           }
       };
       System.setSecurityManager(securityManager);
    }
}

以下代码将阻止您使用exit（0）终止代码！