Question: What are Checked Exceptions? Give an example.

Answer:

In Java, Checked Exceptions are exceptions that are checked at compile time by the Java compiler. This means that the compiler enforces the handling of these exceptions, either by using a try-catch block or by declaring them in the method signature using the throws keyword.

Characteristics of Checked Exceptions:

1. Checked at Compile Time: Checked Exceptions are verified by the compiler during the compilation process.
2. Must be Handled: Code that may throw Checked Exceptions must be enclosed within a try-catch block or declared to be thrown using the throws keyword.
3. Subclass of Exception: Checked Exceptions are subclasses of the Exception class but not subclasses of RuntimeException.

Example of Checked Exception:

Consider the FileNotFoundException, which occurs when attempting to access a file that does not exist:

import java.io.FileReader;
import java.io.FileNotFoundException;

public class Main {
    public static void main(String[] args) {
        try {
            FileReader fileReader = new FileReader("file.txt"); // Attempt to open a file
        } catch (FileNotFoundException e) { // Handling FileNotFoundException
            System.out.println("File not found: " + e.getMessage());
        }
    }
}

Explanation:

• In this example, the FileReader constructor may throw a FileNotFoundException if the specified file does not exist.
• To handle this checked exception, we enclose the FileReader instantiation within a try-catch block.
• If a FileNotFoundException occurs, the catch block executes, and an appropriate message is printed.

Benefits of Checked Exceptions:

1. Forces Error Handling: Checked Exceptions ensure that developers handle potential error conditions, leading to more robust and reliable code.
2. Enhances Code Readability: By explicitly specifying the exceptions that a method may throw, Checked Exceptions improve code documentation and readability.
3. Encourages Defensive Programming: Developers are prompted to anticipate and handle exceptional scenarios, resulting in code that gracefully handles error conditions.

Conclusion:

Checked Exceptions in Java provide a mechanism for handling exceptional conditions that may occur during program execution. By enforcing error handling at compile time, Checked Exceptions promote code reliability, maintainability, and robustness.