Throw Clause Example in Java

Introduction

Throw clause is a classic Java console program that demonstrates the concept with complete source code and sample output. Exceptions represent runtime errors; Java uses try-catch-finally to handle them safely.

This tutorial walks through the program line by line, explains how the logic works, and highlights best practices you can apply in your own code.

Syntax

if(<Condition>){
	throw new <ExceptionName>("Exception Statement");
}

Throw clause Example Program

public class ThrowClause {
    //Throw exception if number 1 is greater than 900
    static int add(int num1, int num2){
      if (num1 > 900){
         throw new ArithmeticException("Num 1 is greater than 900 and hence Exception is thrown");
      }else{
         System.out.println("Both parameters are correct!!");
      }
      return num1+num2;
   }
   public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
       System.out.println("Enter number 1 : ");
       int num1 = scanner.nextInt();
       System.out.println("Enter number 2 : ");
       int num2 = scanner.nextInt();
      int result=add(num1,num2);
      System.out.println("Result is : "+result);
   }
}

Sample Output

Enter number 1 : 
100
Enter number 2 : 
200
Both parameters are correct!!
Result is : 300

When to use

Use this throw clause example when learning or revising core Java syntax.

How it works

1. Execution begins in the main method — the JVM calls this method when you run the class.

2. The if statement runs the nested code only when the condition is true.

3. A println / print call writes text to the console — part of the sample output below.

4. A Scanner reads typed input from the keyboard (System.in).

5. A println / print call writes text to the console — part of the sample output below.

6. int num1 = scanner.nextInt(); updates a variable used in the calculation or output.

7. A println / print call writes text to the console — part of the sample output below.

8. A println / print call writes text to the console — part of the sample output below.

Best Practices

• Use meaningful variable and class names that describe their purpose.
• Compile and run the program locally — modify values to see how output changes.
• Read compiler errors carefully; they usually point to the exact line to fix.

Common Mistakes

• Copying code without understanding each line — practice by changing one statement at a time.
• Mismatching the public class name and the .java filename.
• Forgetting semicolons at the end of statements.