我想知道应届生能进bat的水平是怎么样的，我想进bat

怎么样一句话就能让外行人，明白什么是多态

请问找第一份工作时需要注意什么？比如公司是做什么的？公司用的技术？打扰了

打了很久的代码，还是一直卡住，局部内部类的具体用处也不清楚
大佬帮我看下代码呗
https://paste.ubuntu.com/p/2jBzfXPCW7/

老哥带带我呢

[{"name":"jjx","params":{"e":2},"period":"day","symbol":"1173","time":1086883200000,"value":{"single":[{"volume":0,"price":384.3,"time":1086883200000,"type":"open","direction":"less"}],"price":384.3}},{"name":"jjx","params":{"e":2},"period":"day","symbol":"1173","time":1088006400000,"value":{"single":[{"volume":0,"price":402.0,"time":1088006400000,"type":"clean","direction":"less"},{"volume":0,"price":402.0,"time":1088006400000,"type":"open","direction":"more"}],"price":402.0}},{"name":"jjx","params":{"e":2},"period":"day","symbol":"1173","time":1089129600000,"value":{"single":[{"volume":0,"price":402.2,"time":1089129600000,"type":"clean","direction":"more"}],"price":402.2}},{"name":"jjx","params":{"e":2},"period":"day","symbol":"1173","time":1089216000000,"value":{"single":[{"volume":0,"price":407.6,"time":1089216000000,"type":"open","direction":"more"}],"price":407.6}},{"name":"jjx","params":{"e":2},"period":"day","symbol":"1173","time":1090425600000,"value":{"single":[{"volume":0,"price":393.5,"time":1090425600000,"type":"clean","direction":"more"}],"price":393.5}}]
这是一个标准的Json吗？是的话我用String json = 却一直报错呢