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POHibernate 3 createQuery() returning NPE for a basic join - what's wrong?
 

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  1. POHibernate 3 createQuery() returning NPE for a basic join - what's wrong?
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    <p>I'm getting a NPE in <code>createQuery</code> when I try to do a simple many-to-one join using hibernate 3.3.0. I've already elminated possibilities like empty tables and bad entity mappings, nonexistent sessions, etc. but I am new to hibernate annotations so I'm not 100% sure my annotations are correct. I'm thinking there may be an annotation or two I'm missing here, or a syntactic error in the HQL itself, but I'm not sure where to go from here.</p> <p>I have two tables, <code>EventsJobs</code> and <code>EventsJobsTags</code> which share a common attribute, <code>docId</code>. There's a many-to-one relation between the two such that one record in <code>EventsJobs</code> can have many records in <code>EventsJobsTags</code>.</p> <p>My classes (imports/getters/setters/constructors omitted for brevity):</p> <pre><code>package com.x.y.model; @Entity @Table(name = "EventsJobs") public class EventJob { @JoinColumn(name="docId") @Id @Column(name = "docId") private String docId; @Column(name="title") private String title; @Column(name="url") private String url; @Column(name="docType") private String docType; @Column(name="fileName") private String fileName; } </code></pre> <p>and</p> <pre><code>package com.x.y.model; @Entity @Table(name = "EventsJobsTags") public class EventJobTag { @JoinColumn(name="docId") @Id @Column(name = "docId") private String docId; @Column(name = "taxonomyId") private int taxonomyId; @Column(name = "tag") private String tag; } </code></pre> <p>The query:</p> <pre><code>Query q = sessionFactory.getCurrentSession().createQuery(" from com.x.y.model.EventJobTag as et left join com.x.y.model.EventJob as e where e.docType = 'jobs' and et.taxonomyId in ('6079')") .setString("docType", type) .setString("search", search); </code></pre> <p>The stacktrace:</p> <pre><code>SEVERE: Servlet.service() for servlet [xyz] in context with path [/abc] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause java.lang.NullPointerException at org.hibernate.hql.ast.HqlSqlWalker.createFromJoinElement(HqlSqlWalker.java:320) at org.hibernate.hql.antlr.HqlSqlBaseWalker.joinElement(HqlSqlBaseWalker.java:3275) at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3067) at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:2945) at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:688) at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:544) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:281) at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:229) at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:228) at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:160) at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:111) at org.hibernate.engine.query.HQLQueryPlan.&lt;init&gt;(HQLQueryPlan.java:77) at org.hibernate.engine.query.HQLQueryPlan.&lt;init&gt;(HQLQueryPlan.java:56) at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:72) at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:133) at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:112) at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1623) at com.x.y.dao.SearchResultsDaoImpl.searchResults(SearchResultsDaoImpl.java:30) at com.x.y.dao.SearchResultsDaoImpl.jobResults(SearchResultsDaoImpl.java:20) at com.x.y.service.ResumeServiceImpl.listJobs(ResumeServiceImpl.java:45) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:318) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) at $Proxy17.listJobs(Unknown Source) at com.x.y.controller.ResumeController.taxonomySearch(ResumeController.java:163) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:436) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:424) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789) at javax.servlet.http.HttpServlet.service(HttpServlet.java:641) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:680) </code></pre>
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