2 Answers. You have issue with too many connections which leads to unavailability to establish any new connections. The solution is quite simple - you have to setup connection pool (c3p0 is quite popular) and specify pool connections. For me, the problem solved by making sure that all the sessions are closed properly immediately after use. Hibernate uses it to delay the execution of write operations as long as possible. That provides multiple performance benefits, e.g., Hibernate executes 1 SQL UPDATE statement before committing the database transaction instead of executing an UPDATE statement after every call of a setter method. Get early access and see previews of new features. nested exception is org.hibernate.service.spi.ServiceException: Unable to create requested service [org HTTP Status 500 - Request processing failed; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not execute query type Exception report message Request processing failed; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not ixqRzj.

jdbc exception on hibernate data access