我正在努力找出为什么我得到一个空指针异常。我知道这是因为null，但我似乎无法找到哪一个

Here is the code. When I started to run the program I entered the option number 1 and it gave me an error saying Exception in thread "main" java.lang.NullPointerException. Any help would be appreciated.Here is the code. When I started to run the pro