TestNG @BeforeClass Annotation

@BeforeClass: The @BeforeClass annotated method runs before the execution of test methods in a current class.

Let's understand the concept of @BeforeClass annotation through an example:

Step 1: Open the Eclipse.

Step 2: We create a simple java project.

Class1.java

package com.javatpoint;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;

public class Class1 
{
 @BeforeClass
 public void before_class()
 {
	 System.out.println("This method is executed before Class1");
 }
 @Test
 public void testcase2()
 {
	 System.out.println("Test case2");
 }
 @Test
 public void testcase1()
 {
	 System.out.println("Test case1");
 }
}

Class2.java

package com.javatpoint;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;
public class Class2 
{
 @BeforeClass
 public void before_class()
 {
	 System.out.println("This method is executed before Class2");
 }
 @Test
 public void testcase3()
 {
	 System.out.println("Test case3");
 }
 @Test
 public void testcase4()
 {
	 System.out.println("Test case4");
 }
}

We use the @BeforeClass annotated method in the above two classes. Class1 contains the @BeforeClass annotated method, i.e., before_class() which will be invoked before the execution of Class1 and Class2 also contains the @BeforeClass annotated method, i.e., before_class() which will be invoked before the execution of Class2.

Step 3: Now, we create the testng.xml file to configure the above two classes, i.e., Class1 and Class2.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="test_suite">
<test name="Before Class">
<classes>
<class name="com.javatpoint.Class1"/>
<class name="com.javatpoint.Class2"/>
</classes>
</test> <!-- Test -->
</suite> <!-- Suite -->

Step 4: Run the testng.xml file. Right click on the testng.xml file, move the cursor down to Run As and then click on the 1 TestNG Suite.

Output