请问老师，我配置重启三次，但是本地才抛了一次异常就结束了 是什么情况？
public class CheckpointApp {
public static void main(String[] args) throws Exception {
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

    env.enableCheckpointing(5000);
    // 自定义设置我们需要的重启策略
    env.setRestartStrategy(RestartStrategies.fixedDelayRestart(
            3, // 尝试重启的次数
            Time.of(5, TimeUnit.SECONDS) // 间隔
    ));




    DataStreamSource<String> source = env.socketTextStream("localhost", 9527);
    source.map(new MapFunction<String, String>() {
        @Override
        public String map(String value) throws Exception {
            if(value.contains("pk")) {
                throw new RuntimeException("PK哥来了，快跑..");
            } else {
                return value.toLowerCase();
            }
        }
    })
            .print();
    env.execute("CheckpointApp");
}

}