Exception Handling in Java

Exception Handling is a mechanism to handle runtime errors. It is mainly used to handle checked exceptions. If there is any exception at runtime, the program terminates abruptly and the rest of the code is not executed. So, it is always a good practice to handle exceptions.

Types of Exceptions

There are two types of exceptions in Java:

1. Checked Exception
2. Unchecked Exception

Checked Exception

Checked exceptions are checked at compile-time. If some code within a method throws a checked exception, then the method must either handle the exception or it must specify the exception using throws keyword.

Unchecked Exception

Unchecked exceptions are not checked at compile-time, but they are checked at runtime. If an unchecked exception occurs in the code, the program terminates abruptly.

Exception Handling Keywords

There are 5 keywords used in exception handling:

1. try
2. catch
3. finally
4. throw
5. throws

try

The try block is used to enclose the code that might throw an exception. It must be followed by either catch or finally block.

catch

The catch block is used to handle the exception. It must be preceded by try block. g

finally

The finally block is used to execute the important code of the program. It is executed whether an exception is handled or not.

throw

The throw keyword is used to throw an exception explicitly.

throws

The throws keyword is used to declare an exception. It doesn't handle the exception, it just specifies the exception that might occur in the method.

Example

public class ExceptionHandling {
    public static void main(String[] args) {
        try {
            int a = 10 / 0; // ArithmeticException
        } catch (ArithmeticException e) {
            System.out.println("Arithmetic Exception: " + e);
        } finally {
            System.out.println("Finally block is always executed");
        }
    }
}

Arithmetic Exception: java.lang.ArithmeticException: / by zero
Finally block is always executed

In the above example, the code inside the try block throws an ArithmeticException. The catch block catches the exception and prints the message. The finally block is always executed whether an exception is handled or not.

Conclusion

Exception Handling is a mechanism to handle runtime errors. It is mainly used to handle checked exceptions. There are two types of exceptions in Java: Checked Exception and Unchecked Exception. There are 5 keywords used in exception handling: try, catch, finally, throw, and throws.