Ensure your hibernate-core version matches other modules like hibernate-validator or hibernate-entitymanager to avoid conflict.
For older versions (e.g., Hibernate 3.x to 5.x), download the full distribution ZIP from SourceForge or Hibernate.org and look for hibernate-core.jar in the lib/required/ folder. Common Issues & Solutions org.hibernate.hibernateexception jar download
If using a WAR file, the JAR must be placed in the WEB-INF/lib folder. Hibernate 3.x to 5.x)