Criteria API based on MapKeyColumn is not working ------------------------------------------------- Key: JPA-15 URL: http://opensource.atlassian.com/projects/hibernate/browse/JPA-15 Project: Java Persistence API Issue Type: Bug Environment: Hibernate 3.6.1 MySQL 5.0 Reporter: Edwin Dalorzo Attachments: log.txt, src.zip I defined an Employee entity having a map of phone numbers, where the key is the type of phone (home, office, mobile) and the value is the phone number as a String. @ElementCollection(fetch=FetchType.LAZY) @CollectionTable(name="emp_phone") @MapKeyColumn(name="phone_type") @Column(name="phone_num") private Map<String, String> phoneNumbers; Then I tried to write a Criteria API query using a map join, like this: CriteriaBuilder builder = entityManager.getCriteriaBuilder(); CriteriaQuery<Employee> criteria = builder.createQuery(Employee.class); Root<Employee> employeeRoot = criteria.from(Employee.class); criteria.select(employeeRoot); MapJoin<Employee, String, String> phoneRoot = employeeRoot.joinMap("phoneNumbers"); criteria.where(builder.equal(phoneRoot.key(), "HOME")); System.out.println(entityManager.createQuery(criteria).getResultList()); You get an NullPointerException java.lang.NullPointerException at org.hibernate.ejb.criteria.path.AbstractPathImpl.prepareAlias(AbstractPathImpl.java:246) at org.hibernate.ejb.criteria.path.AbstractPathImpl.render(AbstractPathImpl.java:253) at org.hibernate.ejb.criteria.predicate.ComparisonPredicate.render(ComparisonPredicate.java:173) at org.hibernate.ejb.criteria.QueryStructure.render(QueryStructure.java:258) at org.hibernate.ejb.criteria.CriteriaQueryImpl.render(CriteriaQueryImpl.java:340) at org.hibernate.ejb.criteria.CriteriaQueryCompiler.compile(CriteriaQueryCompiler.java:223) at org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:441) at com.dalorzo.Main.main(Main.java:57) Exception in thread "main" java.lang.RuntimeException: java.lang.NullPointerException at com.dalorzo.Main.main(Main.java:64) Caused by: java.lang.NullPointerException at org.hibernate.ejb.criteria.path.AbstractPathImpl.prepareAlias(AbstractPathImpl.java:246) at org.hibernate.ejb.criteria.path.AbstractPathImpl.render(AbstractPathImpl.java:253) at org.hibernate.ejb.criteria.predicate.ComparisonPredicate.render(ComparisonPredicate.java:173) at org.hibernate.ejb.criteria.QueryStructure.render(QueryStructure.java:258) at org.hibernate.ejb.criteria.CriteriaQueryImpl.render(CriteriaQueryImpl.java:340) at org.hibernate.ejb.criteria.CriteriaQueryCompiler.compile(CriteriaQueryCompiler.java:223) at org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:441) at com.dalorzo.Main.main(Main.java:57) If you change the query to filter on value instead of key, it works just fine criteria.where(builder.equal(phoneRoot.value(), "88750372")); I have attached a log with exceptions as well as the Employee entity and the Main class containing a main method. Also, the code in question runs perfectly fine in EclipseLink. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://opensource.atlassian.com/projects/hibernate/secure/Administrators.... - For more information on JIRA, see: http://www.atlassian.com/software/jira