Java Development — Quanture Standards

Stack

• Java 17+ (LTS)
• Spring Boot 3.x
• Maven (preferred) or Gradle
• JUnit 5 + Mockito for tests

Project structure

src/
├── main/java/com/quanture/
│   ├── controller/     # REST endpoints
│   ├── service/        # business logic
│   ├── repository/     # data access (JPA)
│   ├── model/          # entities/DTOs
│   └── config/         # configuration
└── test/java/com/quanture/

REST controller pattern

@RestController
@RequestMapping("/api/v1/items")
@RequiredArgsConstructor
public class ItemController {

    private final ItemService itemService;

    @GetMapping("/{id}")
    public ResponseEntity<ItemDto> getItem(@PathVariable Long id) {
        return ResponseEntity.ok(itemService.findById(id));
    }

    @PostMapping
    public ResponseEntity<ItemDto> createItem(@Valid @RequestBody CreateItemRequest req) {
        return ResponseEntity.status(201).body(itemService.create(req));
    }
}

Security rules

• Never store credentials in application.properties in plaintext
• Use application.yml with environment variable references:

  spring:
    datasource:
      password: ${DB_PASSWORD}

• Enable Spring Security on all endpoints by default — whitelist exceptions explicitly
• Use @PreAuthorize for method-level security
• Validate all inputs with @Valid + Bean Validation annotations
• Never expose stack traces in API responses — use @ControllerAdvice

Exception handling

@RestControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(ResourceNotFoundException.class)
    public ResponseEntity<ErrorResponse> handleNotFound(ResourceNotFoundException e) {
        return ResponseEntity.status(404).body(new ErrorResponse(e.getMessage()));
    }
}

JPA entity

@Entity
@Table(name = "items")
@Data
@NoArgsConstructor
public class Item {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false)
    private String name;

    @CreationTimestamp
    private LocalDateTime createdAt;
}

SQL — parameterized queries only

// GOOD (Spring Data JPA)
Optional<Item> findByNameAndActive(String name, boolean active);

// GOOD (JPQL)
@Query("SELECT i FROM Item i WHERE i.name = :name")
List<Item> findByName(@Param("name") String name);

// NEVER — native string concat with user input

Advanced reference

• Spring Security: See reference/security.md
• Testing: See reference/testing.md
• Database migrations: See reference/migrations.md