Consider this test class:

Consider this test class:

@WebMvcTest(controllers = ProductController.class)
class ProductControllerTest {
  @Autowired
  private MockMvc mockMvc;

  @MockBean
  private ProductService productService;

  @Test
  void testGetProduct() throws Exception {
    when(productService.getProduct(1L)).thenReturn(new Product(1L, "Book"));
    mockMvc.perform(get("/products/1"))
      .andExpect(status().isOk())
      .andExpect(jsonPath("$.name").value("Book"));
  }
}

What is the purpose of the @MockBean annotation here?