Question

please verify me if I am right: when a program encounters a exception we should write code to handle that exception, the handler should do some recovery job, like rerun the program, but is not just telling us where we went wrong in real world application.

Answer 1

When you throw an exception you’re saying:
“Something happened and I can’t handle it here. I’m passing the buck!”

When you catch you say:
“Ok I can do something. Perhaps loop around and try again; maybe log an error message”.
You can even choose to ignore the error but that’s usually discouraged.

In general the thrower captures the state of the failure and the catcher acts on the failure.
In real life, exceptions don’t always make error handling easier; but it helps keeps errors out of the main line code path. It’s an alternate execution flow. You often hear this: “Exceptions should be used only for exceptional things.”