Throws keyword in Java - Mini Project: Build & Apply

Handling Exceptions with the Throws Keyword in Java

📖 Scenario: Imagine you are writing a simple Java program that reads a number from the user and divides 100 by that number. Sometimes, the user might enter zero, which causes an error called ArithmeticException. To handle this, you will use the throws keyword to declare that your method might throw an exception.

🎯 Goal: You will create a method that divides 100 by a number given as input. You will declare that this method throws an ArithmeticException. Then, you will call this method from main and print the result.

📋 What You'll Learn

Create a method called divide that takes an int parameter called number.

Declare that divide throws ArithmeticException.

Inside divide, return the result of dividing 100 by number.

In the main method, call divide with the value 0.

Print the result of the divide method call.

💡 Why This Matters

🌍 Real World

In real programs, methods often need to declare exceptions they might throw so callers know to handle errors like dividing by zero or file not found.

💼 Career

Understanding the <code>throws</code> keyword is essential for writing robust Java applications that handle errors properly, a key skill for Java developers.

1

Create the divide method signature

Write a method called divide that takes an int number parameter and declares it throws ArithmeticException. Do not write the method body yet.

Java

public class ThrowsExample {

    public static void main(String[] args) {

    }

    // Write the divide method signature here
    // Your code here
}

Need a hint?

Remember to include throws ArithmeticException after the method parameters.

2

Implement the divide method body

Inside the divide method, return the result of dividing 100 by the parameter number.

Java

public class ThrowsExample {

    public static void main(String[] args) {

    }

    public static int divide(int number) throws ArithmeticException {
        // Return 100 divided by number
        // Your code here
    }
}

Need a hint?

Use the division operator / to divide 100 by number.

3

Call divide method from main

In the main method, call the divide method with the argument 0 and store the result in an int variable called result.

Java

public class ThrowsExample {

    public static void main(String[] args) {
        // Call divide with 0 and store in result
        // Your code here
    }

    public static int divide(int number) throws ArithmeticException {
        return 100 / number;
    }
}

Need a hint?

Remember to assign the call to divide(0) to a variable named result.

4

Print the result

Add a System.out.println statement in the main method to print the value of result.

Java

public class ThrowsExample {

    public static void main(String[] args) {
        int result = divide(0);
        // Print the result
        // Your code here
    }

    public static int divide(int number) throws ArithmeticException {
        return 100 / number;
    }
}

Need a hint?

When you run this code, it will throw an exception because dividing by zero is not allowed.