LocalDateTimeとInstantの違いはこれがわかりやすいと思う stackoverflow.com/a/32443004 #DroidKaigi

1. Czasy jako String - to jest proszenie się o poważne problemy na dzień dobry - powinien być LocalDateTime albo inny obiekt 2. Miasta jako Stringi - no bo nie wiadomo o jakie miasta może chodzić, bo mogą być: - Wroclaw Glowny - Wrocław - Breslau Hbf - Wroclaw Central W zależności od języka użytkownika podróżującego można używać różnych nazw tej samej stacji. 3. Statusy jako Stringi - powinien być enum class albo sealed class, a nie "On Time", "Delayed Xm", "Boarding" jako stringi. 4. TrainConnection miesza dane rozkładowe, biletowe i UI - to jest zły design modelu i łamanie zasady pojedynczej odpowiedzialności. Już pierwsza klasa, a tyle do poprawy.

今日(5/5)のお仕事完了 PostgreSQL の timestamptz に Java の LocalDateTime 入れてタイムゾーンに苦しめられるの巻(1年ぶり2度目)。 「はなから OffsetDateTime 使え」の札ぶら下げてる

UTC 完全に理解した‼️ Kotlin で言うと、Instant と LocalDateTime をいままで何となく使ってしまっていた

Java 17 Records – perfect DTOs for Spring Boot APIs 
Tired of boilerplate DTOs with getters, setters, equals, and hashCode? Java 17 Records got your back 👀 public record OrderDto(String id, BigDecimal amount, LocalDateTime placedAt) {} Immutable by default, super clean in controllers & services. 
Pro tip: Pair with @JsonProperty for custom JSON names. Used this in a recent high-traffic service – code became 40% shorter. Game changer? Yes. #Java17 #SpringBoot

Every Kafka serializer I write follows the same pattern: JsonMapper.builder().findAndAddModules().build() The findAndAddModules() call picks up JavaTimeModule automatically. This handles Instant and LocalDateTime serialization without manual registration.

2️⃣ A simpler way is to make compose interpret List, Set and Map as stable in your project. This can be done by specifying them in a stability config. In such a config we might also want to add other types, like LocalDateTime. However, this solution is unsafe, as it can lead to problems if we pass a mutable collection hidden behind a read-only interface. So if you choose this solution, you need to be really careful to not pass to your composables any collections that can be mutated. ‼️

Is there a best practice for storing dates in @MongoDB ? I had some troubles with storing java-time.LocalDateTime and switched to using Instant, but maybe I just don't know how to cook LocalDateTime...

흑흑쉬바 오늘도 LocalDateTime 덕지덕지 붙어있는 소스코드 보면서 눈물을 흘린다

If you are appearing for Java interviews in 2026, Java 8 should be one topic that you need to prepare extensively. Interview questions: LAMBDA & FUNCTIONAL INTERFACE 1. What is a functional interface? 2. Is @FunctionalInterface mandatory? 3. Can a functional interface have default methods? 4. Why were lambdas introduced? 5. Lambda vs anonymous class STREAM API (MOST IMPORTANT) 6. Stream vs Collection 7. Intermediate vs Terminal operations 8. map() vs flatMap() 9. filter() vs map() 10. findFirst() vs findAny() 11. limit() vs skip() 12. peek() – real use case 13. forEach vs forEachOrdered 14. reduce() explained with example 15. collect() – internal working 16. groupingBy() vs partitioningBy() 17. How to remove duplicates using Stream? 18. Parallel stream – when NOT to use? 19. Stream performance vs for-loop 20. Can we reuse a stream? 21. Lazy evaluation in streams OPTIONAL (Tricky area) 22. Why Optional was introduced? 23. orElse vs orElseGet 24. Can Optional be null? 25. Is Optional Serializable? 26. Best practices for using Optional in APIs DEFAULT & STATIC METHODS (Interfaces) 32. Why default methods were introduced? 33. Multiple interface default method conflict – how resolved? 34. Can a default method be overridden? ' 35. Static methods in interface – use case? DATE & TIME API 27. Date vs LocalDate 28. LocalDate vs LocalDateTime 29. ZonedDateTime – real use case 30. How to convert String to LocalDate? 31. Thread safety of Java 8 Date-Time API

아오 일러스타 얘네도 LocalDateTime 쓰네

저희 코드가 Instant 써야 될 데 LocalDateTime 써놓고 수동으로 UTC KST 변환하고 있는 부분이 많아서 마음이 많이 불편해요 의도된대로 타입이 정확하게 쓰이는 게 좋아요

Query #JPA LocalDateTime Using LocalDate Example - #Java Code Geeks javacodegeeks.com/query-jpa-…

How to Query JPA LocalDateTime Field With a LocalDate Value buff.ly/lOgH88I

Well, in this case, the backend and mobile teams are just me 🤦‍♂️ Other than that, you're absolutely correct: client sends LocalDateTime in its own timezone. Backend assumes UTC. Boom. The tricky point is that, if you test in just one timezone, client-backend comms work fine.

LocalDateTime ~> implicit local timezone ~> serializes without ZoneInfo ~> backend parses it its own local timezone. ~> 💥 Instant ~> converted to UTC timezone. no confusion. I see the problem and fight with the backend and mobile teams to get this right.

⚠️ Was performing a routine refactor and cleanup of the backend code, and it just occurred to me that I send serialized LocalDateTime in the default timezone from the clients, but deserialize into Instant on the backend side (and vice-verso for the responses). See the problem?

Sifuder, tratar naive date em Java é um porre! Tenho que fazer parse, transformar em Zoned de UTC, converter para o TZ da máquina e depois convertar de volta para LocalDateTime pro driver do Postgres não ficar chateado comigo.

Es un buen momento para repasar la diferencia entre Instant vs LocalDateTime.

11 Examples of LocalDate, LocalTime, and LocalDateTime in Java 8 dlvr.it/TMZm9z #corejava #dateandtime