Question:

In a Java program, explain the purpose and usage of try-catch blocks. Provide an example of a situation where a try-catch block could be used and the expected behavior when an exception is caught.

Answer:

A try-catch block is a programming construct used to handle exceptions in Java. Exceptions are unexpected events that occur during the execution of a program, such as division by zero, accessing an array out of bounds, or opening a file that does not exist. By using try-catch blocks, we can catch these exceptions, handle them gracefully, and prevent the program from crashing.

Here's an example of a situation where a try-catch block could be used:

public class DivideNumbers {
    public static void main(String[] args) {
        int numerator = 10;
        int denominator = 0;
        
        try {
            int result = numerator / denominator;
            System.out.println("Result: " + result);
        } catch (ArithmeticException e) {
            System.out.println("Error: Division by zero!");
        }
    }
}

In this example, we have a division operation where the denominator is set to 0. This is an invalid operation and will throw an ArithmeticException at runtime.

The try block encompasses the division operation, and if an exception occurs within this block, it is caught by the corresponding catch block. In this case, the ArithmeticException is caught, and the catch block executes, printing the message "Error: Division by zero!".

The expected behavior when an exception is caught is that the program will continue execution from the catch block and prevent the exception from crashing the program. In this example, instead of encountering a runtime error and terminating, the program will print the error message and continue executing any remaining code after the try-catch block.

Using try-catch blocks allows us to handle exceptional scenarios and react accordingly, ensuring that our program does not unexpectedly terminate when faced with errors.