affaan-m
Java coding standards for Spring Boot services: naming, immutability, Optional usage, streams, exceptions, generics, and project layout.
bunx add-skill affaan-m/everything-claude-code -s java-coding-standardsLoadingβ¦
Standards for readable, maintainable Java (17+) code in Spring Boot services.
// β
Classes/Records: PascalCase
public class MarketService {}
public record Money(BigDecimal amount, Currency currency) {}
// β
Methods/fields: camelCase
private final MarketRepository marketRepository;
public Market findBySlug(String slug) {}
// β
Constants: UPPER_SNAKE_CASE
private static final int MAX_PAGE_SIZE = 100;
// β
Favor records and final fields
public record MarketDto(Long id, String name, MarketStatus status) {}
public class Market {
private final Long id;
private final String name;
// getters only, no setters
}
// β
Return Optional from find* methods
Optional<Market> market = marketRepository.findBySlug(slug);
// β
Map/flatMap instead of get()
return market
.map(MarketResponse::from)
.orElseThrow(() -> new EntityNotFoundException("Market not found"));
// β
Use streams for transformations, keep pipelines short
List<String> names = markets.stream()
.map(Market::name)
.filter(Objects::nonNull)
.toList();
// β Avoid complex nested streams; prefer loops for clarity
MarketNotFoundException)catch (Exception ex) unless rethrowing/logging centrallythrow new MarketNotFoundException(slug);
public <T extends Identifiable> Map<Long, T> indexById(Collection<T> items) { ... }
src/main/java/com/example/app/
config/
controller/
service/
repository/
domain/
dto/
util/
src/main/resources/
application.yml
src/test/java/... (mirrors main)
private static final Logger log = LoggerFactory.getLogger(MarketService.class);
log.info("fetch_market slug={}", slug);
log.error("failed_fetch_market slug={}", slug, ex);
@Nullable only when unavoidable; otherwise use @NonNull@NotNull, @NotBlank) on inputsRemember: Keep code intentional, typed, and observable. Optimize for maintainability over micro-optimizations unless proven necessary.
Use when you need to run Flow type checking, or when seeing Flow type errors in React code.
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Use when you need to check feature flag states, compare channels, or debug why a feature behaves differently across release channels.