createQuery(HQL) returns Nullpointerexception when trying to perform LEFT OUTER JOIN

Question

Personal talk,

I have a problem trying to run an HQL on my application.

The HQL is basically this:

select c.id, c.solicitante from <mypackage>.Exame c
LEFT OUTER JOIN <mypackage>.Profissional prof

Java code:

hql = "select c.id, c.solicitante from <mypackage>.Exame c LEFT OUTER JOIN <mypackage>.Profissional prof";
session = HibernateUtil.currentSession();
Query query = session.createQuery(hql);//o erro acontece aqui

and Exception is as follows:

Caused by: java.lang.NullPointerException
at <mypackage>.DaoBase.executarQuery(DaoBase.java:129)
at <mypackage>.RelatoriosBean.gerarRelatorio(RelatoriosBean.java:73)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at javax.el.BeanELResolver.invokeMethod(BeanELResolver.java:779)
at javax.el.BeanELResolver.invoke(BeanELResolver.java:528)
at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:257)
at com.sun.el.parser.AstValue.invoke(AstValue.java:248)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:302)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:148)

I’m not an expert on HQL but I know there’s no need to spell out a clause WITH after the JOIN.

I don’t really know what it can be. It happens with any relationship I have in my class. As it is a reporting tool, if I select only primitive type fields (e.g.: String, Integer, etc.) HQL runs normally.

And yes, I did a lot of research on how to develop the HQL, I also looked to see if anyone has ever come across this problem but so far no proposed solution has helped me...

From now on I appreciate any help!

Answer 1

in fact the query should be as follows:

select c.id, c.solicitante from <mypackage>.Exame c LEFT OUTER JOIN c.solicitante prof

i.e., use the attribute name instead of the class name (being c.applicant the attribute name within the class <mypackage>.Exame)

Anyway, this is it!