Hibernate 5.2.10 DDL auto-update to AWS RDS (MySql 5.6.10a) creates TINYBLOB for Instant

Question

I have a JPA @Entity with an @Column of type java.time.Instant. My understanding is this should map to a column type of TIMESTAMP. However, Hibernate auto-update created the column with type TINYBLOB, and the data it stores there is not translatable back to an Instant. I manually updated the @Column type to TIMESTAMP, but Hibernate still fails because it tries to insert data in the TINYBLOB format. I read here that Hibernate 5 handled JDK 8 classes out of the box, so I am wondering why that seems not to be the case. I worked around the problem using java.sql.Timestamp, but I have to ask, is there a way to make Hibernate persist Instant as a Timestamp? Is this an issue with the JDBC driver or the older version of MySQL provided by AWS RDS?

Answer 1

Adding hibernate-java8 dependency should solve your problem. By default, Java's Instant becomes datetime in RDS.

Example for maven pom.xml:

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-java8</artifactId>
    <version>5.1.0.Final</version>
</dependency>