Hibernate/JPA problem when deploying Play app in Servlet Container (jetty)

[Zeph Harben]

I've been developing my Play application as a standalone app, but for
our production environment it will need to be deployed within a Jetty
container.

Here's my problem - say I have a Model mapped as follows :

@Entity
@Table(name = "cms_view")
public class CMS extends GenericModel {

@Column(name="id")
@Id
public String id;

@Column(name="element_type")
public String elementType;

...
}

and a Controller that does this :

public static void index() {
/* Load required cms elements for various parts of the homepage */
CMS element = CMS.find("elementType = ? order by
elementIndex","homepage_element").first();
...
}

In my standalone Play application, this works perfectly - the JPQL
appears to generate the appropriate SQL :

DEBUG ~ select cms0_.id as id43_, cms0_.element_index as element2_43_,
cms0_.element_type as element3_43_ {...} from cms_view cms0_ where
cms0_.element_type=? order by cms0_.element_index limit ?

However, when I use "play war", and deploy the application into a
Jetty Servlet context, the following error occurs when access the
controller (full stacktrace at the end of this message) :

12:30:21,935 DEBUG ~ select cms0_.id as id3_, cms0_.element_index as
element2_3_, cms0_.element_type as element3_3_ {...} from cms_view
cms0_ where (elementType=? ) order by elementIndex limit ?
12:30:21,989 WARN ~ SQL Error: 1054, SQLState: 42S22
12:30:21,989 ERROR ~ Unknown column 'elementType' in 'where clause'
12:30:22,088 ERROR ~

As far as I can tell, when running within the servlet container,
Hibernate/JPA does not properly map the JPQL query's "where" and
"order by" clauses to the Model's underlying entity (our cms_view
table).

When I change my controller to use native SQL, it works fine in both
the standalone and deployed versions :

public static void index() {
/* Load required cms elements for various parts of the homepage */
CMS element = CMS.find("element_type = ? order by
element_index","homepage_element").first();
...
}

We are just beginning to use the Play framework (great job, BTW!), and
we'd strongly like to use the JPQL abstractions instead of native
SQL. Any help will be appreciated!

*** Other Notes : ***
* I have looked into classloader conflicts, but I'm sure if this is
the problem. Our Jetty container does not load any jar's other than
the bare necessities - hibernate, jpa, etc are loaded within specific
web app contexts. I've also set the Play application context to use
"parentLoaderPriority = false" to prevent the parent classloader from
interfering with play.

* A full stacktrace of the error in our Jetty/deployed application :

@659ljjo2c
Internal Server Error (500)

Execution exception (In /app/controllers/Homepage.java around line 28)
JPAQueryException occured : Error while executing query from
models.CMS where elementType = ? order by elementIndex: Unknown column
'elementType' in 'where clause'

play.exceptions.JavaExecutionException: Error while executing query
<strong>from models.CMS where elementType = ? order by elementIndex</
strong>: Unknown column 'elementType' in 'where clause'
at play.mvc.ActionInvoker.invoke(ActionInvoker.java:285)
at play.server.ServletWrapper
$ServletInvocation.execute(ServletWrapper.java:472)
at play.Invoker$Invocation.run(Invoker.java:187)
at play.server.ServletWrapper
$ServletInvocation.run(ServletWrapper.java:463)
at play.Invoker.invokeInThread(Invoker.java:61)
at play.server.ServletWrapper.service(ServletWrapper.java:113)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:
530)
at
org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:
426)
at
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:
119)
at
org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:
494)
at
org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:
229)
at
org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:
931)
at
org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:
361)
at
org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:
186)
at
org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:
867)
at
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:
117)
at
org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:
224)
at
org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:
126)
at
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:
113)
at
org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:
335)
at
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:
113)
at org.eclipse.jetty.server.Server.handle(Server.java:337)
at
org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:
581)
at org.eclipse.jetty.server.HttpConnection
$RequestHandler.headerComplete(HttpConnection.java:1005)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:560)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:
222)
at org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:
417)
at
org.eclipse.jetty.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:
474)
at org.eclipse.jetty.util.thread.QueuedThreadPool
$2.run(QueuedThreadPool.java:437)
at java.lang.Thread.run(Thread.java:636)
Caused by: play.db.jpa.JPABase$JPAQueryException: Error while
executing query <strong>from models.CMS where elementType = ? order by
elementIndex</strong>: Unknown column 'elementType' in 'where clause'
at play.db.jpa.GenericModel$JPAQuery.first(GenericModel.java:301)
at controllers.Homepage.index(Homepage.java:28)
at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:
408)
at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:
403)
at play.mvc.ActionInvoker.invoke(ActionInvoker.java:176)
... 30 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException:
Unknown column 'elementType' in 'where clause'
at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
at com.mysql.jdbc.Util.getInstance(Util.java:384)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3566)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3498)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2113)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2568)
at
com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:
2113)
at
com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:
2275)
at
com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeQuery(NewProxyPreparedStatement.java:
76)
at
org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:
208)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1869)
at org.hibernate.loader.Loader.doQuery(Loader.java:718)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:
270)
at org.hibernate.loader.Loader.doList(Loader.java:2449)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2192)
at org.hibernate.loader.Loader.list(Loader.java:2187)
at
org.hibernate.hql.classic.QueryTranslatorImpl.list(QueryTranslatorImpl.java:
936)
at
org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:
196)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1258)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:241)
at play.db.jpa.GenericModel$JPAQuery.first(GenericModel.java:295)
... 34 more

[Zeph Harben]

Note - in further testing this issue, I found that the following
scenarios worked :
* deploying only the Play application context to Jetty
* configuring the Jetty web application contexts so that the Play
application was initialized/deployed first

The problem occurs when I deploy both our legacy application context,
and the Play application context, and the legacy application context
loads first.

I think I have a workaround for my problem, but if anyone in the
community has any insights, I'd love to know what may be happening
here.

Thanks
- Zeph

[Guillaume Bort]

So it is probably a classloader problem...

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