Checked vs Unchecked Exception

Exceptions

In Java exceptions (which differs from the C exception) there are two types of exceptions.

Checked exceptions

Checked exceptions are exceptions that are checked at compile time. If some code in a method throws a checked exception, then the method must either handle the exception by surrounding it with try-catch or has to throw the exception to make the caller of the method handle it.

Exception such as FileNotFoundException are checked exception that you must handle.

Checked exceptions are sub-class of Exception that aren't sub-class of RuntimeException

Unchecked exceptions

Unchecked exceptions are the opposite that aren't checked by the compiler, therefore, you are not forced to handle it with try-catch. It is up to the programmer to handle it or throw it.

Exception such as NullPointerException are unchecked.

This is why you can use Integer.parseInt without surrounding it with try-catch clause.

Unchecked exceptions are sub-class of RuntimeException

Fun fact: RuntimeException is actually a sub-class of Exception, however, it is treated differently by the compiler to be unchecked exception.