NullPointerException when trying to access database
pebbels Mar 13, 2008 12:58 PMHi guys,
I got stick when trying to ccess the MySQl Database.
persistence.xml looks like this:
<persistence-unit name="fahrzeug_console" transaction-type="JTA"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <jta-data-source>java:/fahrzeug_consoleDatasource</jta-data-source> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="validate"/> <property name="hibernate.show_sql" value="true"/> <property name="hibernate.format_sql" value="true"/> <property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.JBossTransactionManagerLookup"/> </properties> </persistence-unit> </persistence>
And my code looks like this ( the problem occurs in queryVertraege() )
package com.console.beans; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; import java.util.Collection; import java.util.List; import javax.ejb.Remove; import javax.ejb.Stateful; import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.PersistenceContextType; import org.hibernate.annotations.Entity; import org.hibernate.annotations.Table; import org.jboss.seam.annotations.Factory; import org.jboss.seam.annotations.In; import org.jboss.seam.annotations.Name; import org.jboss.seam.annotations.Scope; import org.jboss.seam.annotations.datamodel.DataModel; import org.jboss.seam.annotations.security.Restrict; import org.jboss.seam.ScopeType; import com.console.doing.DBConnection; import org.jboss.seam.security.Identity; @Stateful @Name("vertraege") @Restrict("#{identity.loggedIn}") public class Vertraege { @DataModel private List<Vertrag> vertraege = new ArrayList<Vertrag>(); private int size; @PersistenceContext private EntityManager em; public int getSize() { return size; } public void setSize(int size) { this.size = size; System.out.print("size gesetzt: "+size); } public void queryVertraege() { vertraege = em.createQuery("select Fahrgestellnummer from _Vertrag").getResultList(); } @Remove public void destroy() {} }
This is the bean
package com.console.beans; import java.io.Serializable; import java.util.ArrayList; import java.util.Date; import java.util.List; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.Table; import org.jboss.seam.annotations.Name; import org.jboss.seam.annotations.datamodel.DataModel; @Entity //@Table(name="_Vertrag") @Name("vertrag") public class Vertrag implements Serializable{ private int Fahrgestellnummer; private int id; private Date realesVertragsende; private Date regulaeresVertragsende; @Column(name="Fahrgestellnummer") public int getFahrgestellnummer() { return Fahrgestellnummer; } public void setFahrgestellnummer(int fahrgestellnummer) { Fahrgestellnummer = fahrgestellnummer; } @Id @GeneratedValue @Column(name="ID_Vertrag") public int getId() { return id; } public void setId(int id) { this.id = id; } @Column(name="Reales_Vertragsende") public Date getRealesVertragsende() { return realesVertragsende; } public void setRealesVertragsende(Date realesVertragsende) { this.realesVertragsende = realesVertragsende; } @Column(name="Regulaeres_Vertragsende") public Date getRegulaeresVertragsende() { return regulaeresVertragsende; } public void setRegulaeresVertragsende(Date regulaeresVertragsende) { this.regulaeresVertragsende = regulaeresVertragsende; } @Override public String toString(){ return "Vertrag " +id+ ": Reales Vertragsende " +realesVertragsende+ ", reguläres Vertragsende " +regulaeresVertragsende; } }
the following exception is thrown:
12:24:40,812 FATAL [application] java.lang.NullPointerException javax.faces.el.EvaluationException: java.lang.NullPointerException at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:91) at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:91) at javax.faces.component.UICommand.broadcast(UICommand.java:383) at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:184) at org.ajax4jsf.component.AjaxViewRoot.broadcastEvents(AjaxViewRoot.java:162) at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:350) at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:97) at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:117) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:244) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83) at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:85) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:141) at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:281) at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:60) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:58) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.debug.hot.HotDeployFilter.doFilter(HotDeployFilter.java:68) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:179) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:432) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:262) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:446) at java.lang.Thread.run(Thread.java:619) Caused by: java.lang.NullPointerException at com.console.beans.Vertraege.queryVertraege(Vertraege.java:56) at com.console.beans.Login.login(Login.java:58) 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.jboss.seam.util.Reflections.invoke(Reflections.java:21) at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:31) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56) at org.jboss.seam.transaction.RollbackInterceptor.aroundInvoke(RollbackInterceptor.java:31) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:46) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.bpm.BusinessProcessInterceptor.aroundInvoke(BusinessProcessInterceptor.java:49) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:42) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107) at org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:166) at org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:102) at com.console.beans.Login_$$_javassist_43.login(Login_$$_javassist_43.java) 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.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:329) at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:342) at org.jboss.el.parser.AstPropertySuffix.invoke(AstPropertySuffix.java:58) at org.jboss.el.parser.AstValue.invoke(AstValue.java:96) at org.jboss.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276) at com.sun.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:68) at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:77) ... 46 more
Can somebody please tell me what is wrong?
Do I have to do any configurations?
Thanks Tina