Java Checked Exception and RuntimeException

Java provides two main exception types:

• Runtime Exceptions :Runtime exceptions extend from either java.lang.RuntimeException or java.lang.Error.
• Checked exceptions. All checked exceptions extend from java.lang.Exception

Runtime exceptions

• The method signature does not need to declare runtime exceptions
•  Caller to a method that throws a runtime exception is not forced to catch the runtime exception
•  Runtime exceptions extend from RuntimeException or Error

Checked exceptions:

•  method must declare each checked exception it throws
•  caller to a method that throws a checked exception must either catch the exception or throw the exception itself
•  Checked exceptions extend from Exception

Checked exceptions indicate an exceptional condition from which a caller can conceivably recover. Runtime exceptions indicate a programmatic error from which a caller cannot normally recover.

Checked exceptions force you to catch the exception and to do something about it. You should always catch a checked exception once you reach a point where your code can make a meaningful attempt at recovery. However, it is best not to catch runtimeexceptions. Instead, you should allow runtime exceptions to bubble up to where you can see them.