Why does the exception thrown by some method not need to handle

Question

For example, if I don't handle the NumberFormatException thrown by Integer.parseInt(), it could be complied; however, if I use the Thread.sleep() without a try-catch, there would be the unhandled exception error. Why?

This is related to checked and unchecked exceptions. – Sid Sep 29 '19 at 14:24 — Sid, Sep 29 '19 at 14:24

score 2 · Accepted Answer · answered Sep 29 '19 at 14:15

2

Read the difference between checked exceptions (mandatory to be handled), and non-checked exceptions (optional to be handled) in Java.

answered Sep 29 '19 at 14:15

score 1 · Answer 2 · answered Sep 29 '19 at 14:14

1

NumberFormatException extends RuntimeException. Runtime exceptions are unchecked exceptions and do not need to be caught

answered Sep 29 '19 at 14:14

m0skit0

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score 0 · Answer 3 · answered Sep 29 '19 at 14:22

In short, if a method declares that it might throw an exception, compiler will force you to handle (with catch block) or redeclare it in case that exception is itself or subclass of Exception class.In opposite, if the declared exception is itself or subclass of RuntimeException class, compiler will stay silent and doesn't force you to do something. I also strongly recommend to look into differences between unchecked and checked exceptions as was said in other answers.

Why does the exception thrown by some method not need to handle

3 Answers3