Tablestore:"Unable to instantiate default tuplizer" error when querying data through Hibernate with the JDBC driver for Tablestore

Problem

When you query data by using Hibernate with the Java Database Connectivity (JDBC) driver for Tablestore, the following error occurs:

Exception in thread "main" org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer]
  at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:108)
  at org.hibernate.tuple.entity.EntityTuplizerFactory.constructDefaultTuplizer(EntityTuplizerFactory.java:133)
  at org.hibernate.tuple.entity.EntityEntityModeToTuplizerMapping.<init>(EntityEntityModeToTuplizerMapping.java:80)
  at org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:322)
  at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:485)
  at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:133)
  at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:84)
  at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:286)

Cause

The javassist-x.x.x.jar package is missing from your project's classpath.

Hibernate uses javassist for runtime bytecode manipulation to generate dynamic proxies for entity classes. These proxies enable lazy loading and dirty checking. Without javassist, Hibernate cannot create PojoEntityTuplizer instances, and the query fails.

Solution

Add the javassist library to your project by using one of the following methods.

Method 1: Add a Maven dependency

Add the following dependency to the <dependencies> block in your pom.xml file. This example uses version 3.15.0-GA.

<!-- https://mvnrepository.com/artifact/org.javassist/javassist -->
<dependency>
    <groupId>org.javassist</groupId>
    <artifactId>javassist</artifactId>
    <version>3.15.0-GA</version>
</dependency>

Method 2: Download and import the JAR manually

1. Download the javassist-x.x.x.jar file from Maven Repository, where x.x.x is the version number. Choose a version based on your project requirements.

2. Import the downloaded JAR into your project.

Verify the fix

After you add the javassist dependency, rebuild your project and re-run the query. The Unable to instantiate default tuplizer error no longer appears.