What is TestNG Annotation?

TestNG Annotation is a piece of code which is inserted inside a program or business logic used to control the flow of execution of test methods.

List of TestNG Annotations

TestNG Annotation	Description
@BeforeSuite	The @BeforeSuite annotated method will run before the execution of all the test methods in the suite.
@AfterSuite	The @AfterSuite annotated method will run after the execution of all the test methods in the suite.
@BeforeTest	The @BeforeTest annotated method will be executed before the execution of all the test methods of available classes belonging to that folder.
@AfterTest	The @AfterTest annotated method will be executed after the execution of all the test methods of available classes belonging to that folder.
@BeforeClass	The @BeforeClass annotated method will be executed before the first method of the current class is invoked.
@AfterClass	The @AfterClass annotated method will be invoked after the execution of all the test methods of the current class.
@BeforeMethod	The @BeforeMethod annotated method will be executed before each test method will run.
@AfterMethod	The @AfterMethod annotated method will run after the execution of each test method.
@BeforeGroups	The @BeforeGroups annotated method run only once for a group before the execution of all test cases belonging to that group.
@AfterGroups	The @AfterGroups annotated method run only once for a group after the execution of all test cases belonging to that group.

TestNG Annotations made the life of testers very easy. Based on your requirements, you can access the test methods, i.e., it has no predefined pattern or format.
You can pass the additional parameters to TestNG annotations.
In the case of TestNG annotations, you do not need to extend any test classes.
TestNG Annotations are strongly typed, i.e., errors are detected at the compile time.