What is an Exception ? Briefly explain the causes of Exceptions. Describe how multiple exceptions are caught in Java, with the help of a suitable program code.

An exception in Java is an event that occurs during the execution of a program, disrupting the normal flow of the program. It represents an error or an exceptional condition that can occur at runtime. When an exceptional condition arises, an exception object is created to provide information about the error, and the normal flow of the program is transferred to an appropriate exception-handling code block.

Causes of exceptions in Java can include:

1. Programming errors: These are mistakes made by the developer, such as dividing by zero, accessing an invalid array index, or calling a method with incorrect arguments.

2. Environmental errors: These occur due to external factors, such as unavailable network connections, file system errors, or running out of memory.

3. User errors: These are errors caused by user input, such as entering invalid data or incorrect input formats.

Java provides a mechanism to catch and handle exceptions using try-catch blocks. Multiple exceptions can be caught and handled using multiple catch blocks. Each catch block is responsible for handling a specific type of exception. Here's an example program that demonstrates catching multiple exceptions:

class Control { public static void main(String[] args) { try { int[] numbers = {1, 2, 3}; System.out.println(numbers[5]); // Accessing an invalid array index } catch (ArrayIndexOutOfBoundsException e) { System.out.println("Array index out of bounds exception caught"); } catch (NullPointerException e) { System.out.println("Null pointer exception caught"); } catch (Exception e) { System.out.println("Generic exception caught"); } } }

 

In this program, we attempt to access an element at index 5 in an array that only has 3 elements, causing an `ArrayIndexOutOfBoundsException`. We use multiple catch blocks to handle different types of exceptions:

- The first catch block catches `ArrayIndexOutOfBoundsException` and prints a specific error message.

- The second catch block catches `NullPointerException`, which is not applicable in this case but demonstrates the ability to handle different exceptions.

- The last catch block catches `Exception`, which is a superclass of all exceptions. It acts as a generic catch block to handle any exceptions not caught by the previous catch blocks.

When the program is run, the output will be:

Array index out of bounds exception caught

The specific exception that occurred (`ArrayIndexOutOfBoundsException`) is caught and handled by the appropriate catch block, printing the corresponding error message.