2. What is the difference between Exception and Error?

1. Exception: Some exceptions that may occur during the running of the program are required to be handled or captured by the program.It is because of the design of the program or some input and so on.

Exception is a kind of exception that may occur during java runtime, divided into runtime (unchecked exception) exception and non-runtime exception (checked exception).

1. Runtime exceptions: such as array access subscript out of bounds, null pointer exception, number conversion exception and so on.

Usually programs do not force us to catch such exceptions, but we are encouraged to do so.

2. Non-operation is abnormal: file does not exist, IO exception, etc.

Force we must handle this type of exception: catch it with a try-catch block in the current class, or throw an exception with throws.

The exception is only possible, it does not mean that it must appear, but for this possibility, we will deal with the possibility of this exception in advance.

Second, Error: A system-level error that the program does not have to deal with.For example, insufficient memory space, hardware problems, etc.For this kind of error, the program is basically powerless, and has no choice but to exit the program, which is usually thrown by the java virtual machine.