Exception Handling Example in Java

Introduction

Exception Handling 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.

Definition

Exception handling is the process of responding to the occurrence, during computation, of exceptions ? anomalous or exceptional conditions requiring special processing ? often changing the normal flow of program execution. It is provided by specialized programming language constructs or computer hardware mechanisms.

Syntax

try{
	//Statements
	}catch(Expression_type Variable_name){
		//Statements
	}

Exception Handling Example Program

class ExceptionHandlingExample{
	public static void main(String[] args){
		int num1,num2,num3;
		num1=20;
		num2=0;
		try{
			num3=num1/num2;
			System.out.println("Result is "+num3);
		}catch(ArithmeticException ae){
				System.out.println("Numbers cannot be divided by zero");
			}
	num3=num1+num2;
	System.out.println("Result after addition is "+num3);
	}
}

Sample Output

Numbers cannot be divided by zero
Result after addition is 20

When to use

Use this exception handling 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. num1=20; updates a variable used in the calculation or output.

3. num2=0; updates a variable used in the calculation or output.

4. num3=num1/num2; updates a variable used in the calculation or output.

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

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

7. num3=num1+num2; updates a variable used in the calculation or output.

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.