How to merge entity collections with JPA and Hibernate

Introduction

In this article, you are going to learn why overwriting entity collections is an anti-pattern and how you can merge collections both effectively and efficiently with JPA and Hibernate.

The reason I decided to write this article is that I’ve been this question asked over and over and over again.

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How to map java.time.Year and java.time.Month with JPA and Hibernate

Introduction

In this article, we are going to see how you can map the java.time.Year and java.time.Month with both JPA and Hibernate.

As explained in this article, JPA 2.2 supports LocalDate, LocalTime, LocalDateTime, OffsetTime, OffsetDateTime from the java.time package. Hibernate has been supporting the Java 8 Date/Time classes since 5.0 via the hibernate-java8 dependency, but since version 5.2, this dependency was merged with hibernate-core so you get the Duration, Instant and ZonedDateTime types in addition to the ones supported by JPA 2.2.

However, neither JPA nor Hibernate supports the java.time.Year type out-of-the-box. As you will see, adding support for java.time.Year is very easy with both standard JPA or Hibernate.

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How to map the Java YearMonth type with JPA and Hibernate

Introduction

In this article, we are going to see how you can map a java.time.YearMonth with both JPA and Hibernate.

As I explained in this article, JPA 2.2 supports the following Date/Time types introduced in Java 8:

  • java.time.LocalDate
  • java.time.LocalTime
  • java.time.LocalDateTime
  • java.time.OffsetTime
  • java.time.OffsetDateTime

Apart from supporting those, Hibernate supports also:

  • java.time.Duration
  • java.time.Instant
  • java.time.ZonedDateTime

However, neither JPA nor Hibernate support the java.time.YearMonth out-of-the-box. As you will see, adding support for java.time.YearMonth is really straightforward for both standard JPA or Hibernate.

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