1// Spring Boot REST endpoint
2@RestController
3public class UserController {
4    @GetMapping("/users/{id}")
5    public User getUser(@PathVariable Long id) {
6        return userService.findById(id);
7    }
8}

1// ASP.NET Core equivalent
2[ApiController]
3[Route("[controller]")]
4public class UserController : ControllerBase
5{
6    [HttpGet("{id}")]
7    public User GetUser(long id)
8    {
9        return _userService.FindById(id);
10    }
11}

1// Spring DI
2@Service
3public class OrderService {
4    private final PaymentService paymentService;
5
6    @Autowired
7    public OrderService(PaymentService paymentService) {
8        this.paymentService = paymentService;
9    }
10}

1// .NET DI
2public class OrderService
3{
4    private readonly IPaymentService _paymentService;
5
6    public OrderService(IPaymentService paymentService)
7    {
8        _paymentService = paymentService;
9    }
10}
11
12// Registration in Program.cs
13builder.Services.AddScoped<IPaymentService, PaymentService>();
14builder.Services.AddScoped<OrderService>();

1// JPA entity
2@Entity
3@Table(name = "users")
4public class User {
5    @Id @GeneratedValue
6    private Long id;
7    private String name;
8    private String email;
9}

1// EF Core entity
2public class User
3{
4    public long Id { get; set; }
5    public string Name { get; set; }
6    public string Email { get; set; }
7}
8// DbContext handles table mapping

1// JUnit 5 + Mockito
2@ExtendWith(MockitoExtension.class)
3class UserServiceTest {
4    @Mock UserRepository repo;
5    @InjectMocks UserService service;
6
7    @Test
8    void shouldFindUser() {
9        when(repo.findById(1L)).thenReturn(Optional.of(new User("Alice")));
10        assertEquals("Alice", service.getUser(1L).getName());
11    }
12}

1// xUnit + Moq
2public class UserServiceTest
3{
4    [Fact]
5    public void ShouldFindUser()
6    {
7        var repo = new Mock<IUserRepository>();
8        repo.Setup(r => r.FindById(1)).Returns(new User("Alice"));
9        var service = new UserService(repo.Object);
10        Assert.Equal("Alice", service.GetUser(1).Name);
11    }
12}