Hibernate UUID issues on Postgres 10

After updating a database from Postgres 9.6 to 10 all applications stopped working. The error message in the server log file is “Unable to load requested class: pg-uuid”. 


The software stack in use is

  • Wildfly 10 with Hibernate 5.0.16 (also tested with Wildfly 11 with Hibernate 5.1.10)
  • Postgres JDBC driver 42.1.4
  • Postgres Server 9.6 updated to Postgres Server 10.1

In the entity I have the following annotations

 @Type(type = "pg-uuid")
 private UUID id;


While running on Postgres 9.6 the application was running fine. After the upgrade to 10.1 the application stopped working. The cause is an  exception during startup deployment:

 Caused by: java.lang.ClassNotFoundException: Could not load requested class : pg-uuid"


I have not found the root cause yet, but I was able to resolve the issue. by adding the following line to the application’s persistence.xml.

<property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQL94Dialect"/>

Dialects of Hibernate 5.0 / 5.1 which is used in Wildfly 10 / 11 supports max up to PostgreSQL94Dialect. PostgreSQL95Dialect has been added in Hibernate 5.2

Update 2019-06-19

Since Hibernate 5.4 PostgresSQL10 dialect is available. At the moment of the update current Wildfly version is 17. Wildfly 17 ships with Hiberate 5.3.10 – so PostgreSQL95Dialect is still the latest version to be used.