What is the method used by JUnit for testing?

There are several main methods used in JUnit.

1. @Test annotation: used to identify test methods, JUnit will execute all methods with @Test annotation.
2. @Before annotation: used to identify a method that needs to be executed before each test method, typically used to initialize some shared resources.
3. @After annotation: used to identify a method that needs to be executed after each test method, typically used to release some shared resources.
4. @BeforeClass annotation: used to identify the method that needs to be executed before all test methods, typically used for initializing static resources.
5. @AfterClass annotation: used to identify a method that needs to be executed after all test methods, typically used to release some static resources.
6. The assertEquals() method is used to compare two values and throws an AssertionError if they are not equal.
7. assertTrue() method: used to check if a condition is true, and throws an AssertionError if it is false.
8. The assertFalse() method is used to check if a condition is false, and if it is true, it will throw an AssertionError exception.
9. The assertNull() method is used to check if an object is null, and if it is not null, it will throw an AssertionError exception.
10. The assertNotNull() method is used to determine if an object is not null; if it is null, an AssertionError exception is thrown.

In addition to the methods mentioned above, JUnit also offers various other assertion methods and annotations to support a wider range of testing scenarios and requirements.