Chapter 7.4, Problem 20SC

Program Plan Intro

Exception:

• It is nothing but an undesirable or unexpected event that occurs at run time which interrupts the normal flow of the program’s commands.
• Exception handling is a mechanism that handle runtime errors like “ClassNotFoundException”, “SQLException”, and so on.
• An advantage of exception handling is to maintain a flow of the program.
• An exception can be handled using “try” and “catch” block.

Catching exception:

Java virtual machine (JVM) searches to handle the error in “catch” clause at that time of exception in the program. So “try-catch” statements are used in order to handle those exceptions. The following are the main keywords used in exception handling.

• “try” block: Try block contains the block of statements to monitor the exception and it thrown the exception.
• “catch” block: Catch block catch exception thrown by the try block to handle it.

Types of exceptions:

There are two types of exceptions. They are:

• Checked Exception:
  • A class that inherits a “Throwable” class except “RunTimeException” and “Error” are called as checked exceptions.
  • Example: “IOException”
• Unchecked Exception:
  • A class that inherits a “RunTimeException” class is called as unchecked exceptions.
  • Example: “ArrayIndexOutOfBoundException”