Java Skill

PURPOSE

Enterprise Java development with modern features and frameworks.

CORE COMPETENCIES

Java 21+ Features:
├── Virtual threads
├── Pattern matching
├── Record classes
├── Sealed classes
└── Switch expressions

Spring Boot 3:
├── Native compilation
├── Observability
├── WebFlux (reactive)
└── Data JPA

CODE PATTERNS

Service Pattern

@Service
@RequiredArgsConstructor
public class UserService {
    private final UserRepository repository;

    @Transactional(readOnly = true)
    public Optional<User> findById(Long id) {
        return repository.findById(id);
    }

    @Retryable(maxAttempts = 3)
    public User create(CreateUserRequest req) {
        return repository.save(mapper.toEntity(req));
    }
}

TROUBLESHOOTING

TESTING

@SpringBootTest
class UserServiceTest {
    @MockBean
    private UserRepository repository;

    @Test
    void shouldFindUser() {
        given(repository.findById(1L)).willReturn(Optional.of(user));
        var result = service.findById(1L);
        assertThat(result).isPresent();
    }
}