How to test Exceptions using Java JUnit

Let us take a look at how to test exceptions using Junit.
package org.code2care;

public class Calculation {

	public int divide(int no1, int no2) {
		return no1 / no2;

	public void numberToString(int no) {
		System.out.println("The no. entered is: " + Integer.toString(no));

package org.code2care;

public class CalculationClient {
	public static void main(String[] args) {
		Calculation cal = new Calculation();
		Integer no1 = 20;
		Integer no2 = 10;
		System.out.println(cal.divide(no1, no2));


We have two methods division that can throw ArithmeticException and numberToString that can throw a NullPointerException

Let's write test cases in Java JUnit to test these exceptions.
package myprog;

import org.code2care.Calculation;
import org.junit.Test;

 * JUnit test cases for
 * testing exceptions
 * @author code2care
public class CalculationTest {

	@Test(expected = ArithmeticException.class)
	public void divideTwoNumbersArithmeticExceptionTest() {
		Calculation calculation = new Calculation();
		int no1 = 20;
		int no2 = 0;
		calculation.divide(no1, no2);

	@Test(expected = NullPointerException.class)
	public void noToStringNullPointerExceptionText() {
		Calculation calculation = new Calculation();
		Integer no1 = null;

JUnit test cases in Java to test Exceptions Results

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Rakesh (He/Him) has over 14+ years of experience in Web and Application development. He is the author of insightful How-To articles for Code2care.

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