Checked and Unchecked Exceptions /Chapter 3/ Exception Handling

Checked Exceptions

The exceptions which are checked by the compiler for smooth execution of the program at runtime are called, checked exceptions.

example:-

FileNotFoundException,ServletException etc.

In our java program, if there is a possibility of rising checked exception then mandatory we should handle that checked exception (either by try catch or throws keyword) otherwise, we will get compile time error.

Unchecked Exceptions

The exceptions which are not checked by the compiler whether the programmer is handling or not, such type of exceptions are called Unchecked Exceptions.

example:-

ArithmaticException, ArrayIndexOutOfBoundException , NullPointerException etc

Note:     1. Whether it is checked or unchecked, every exception occurs at runtime only there is no chance of occurring any exception at compile-time.

2. RuntimeException and it's child class, Error and it's child classes are unchecked except these remaining are checked.

Fully checked v/s Partially checked

1. A checked exception is said to be fully checked if and only if all its child classes also checked.
   

   IOException
   InterruptedException
   ServletException

   
    


2. A checked exception is said to be partially checked if and only if some of its child classes are unchecked.
   

   Exception
   Throwable

   
    

Note: The Only possible partially checked exceptions in java are:-

1. Throwable


2. Exception