[resolvido]erro ao salvar

Estou tendo um problema, quando eu clicko em salvar ele da o seguinte erro:

Caused by: java.lang.NullPointerException
	at br.com.rpctv.siseng.entidade.Unidade.toString(Unidade.java:451)
	at java.lang.String.valueOf(String.java:2854)
	at java.lang.StringBuilder.append(StringBuilder.java:128)
	at org.hibernate.event.def.DefaultMergeEventListener.getTransientCopyCache(DefaultMergeEventListener.java:133)

Acredito que nessa parte do log esta o erro, porem irei postar todo o código do erro logo abaixo:

INFO: PWC1412: WebModule[null] ServletContext.log():SessionListener: attributeAdded('6af3eefda64d9ebf0a03b1f19711', 'executivoBean', 'br.com.rpctv.siseng.managedBean.ExecutivoBean@6316cf92')
WARNING: EJB5184:A system exception occurred during an invocation on EJB ContatoFacade, method: public void br.com.rpctv.siseng.Facade.AbstractFacade.salvar(java.lang.Object)
WARNING: javax.ejb.EJBException
	at com.sun.ejb.containers.BaseContainer.processSystemException(BaseContainer.java:5215)
	at com.sun.ejb.containers.BaseContainer.completeNewTx(BaseContainer.java:5113)
	at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4901)
	at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:2045)
	at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:1994)
	at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:222)
	at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:89)
	at $Proxy304.salvar(Unknown Source)
	at br.com.rpctv.siseng.Facade.__EJB31_Generated__ContatoFacade__Intf____Bean__.salvar(Unknown Source)
	at br.com.rpctv.siseng.managedBean.ContatoBean.salvar(ContatoBean.java:84)
	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:601)
	at com.sun.el.parser.AstValue.invoke(AstValue.java:254)
	at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:302)
	at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:39)
	at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
	at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
	at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:148)
	at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
	at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:775)
	at javax.faces.component.UICommand.broadcast(UICommand.java:300)
	at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:786)
	at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1251)
	at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
	at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
	at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
	at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
	at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
	at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:368)
	at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
	at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:97)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:100)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:78)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:35)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:177)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:187)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:79)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.session.ConcurrentSessionFilter.doFilter(ConcurrentSessionFilter.java:109)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
	at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:169)
	at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
	at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
	at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
	at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
	at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
	at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
	at com.sun.grizzly.comet.CometEngine.executeServlet(CometEngine.java:459)
	at com.sun.grizzly.comet.CometEngine.handle(CometEngine.java:316)
	at com.sun.grizzly.comet.CometAsyncFilter.doFilter(CometAsyncFilter.java:87)
	at com.sun.grizzly.arp.DefaultAsyncExecutor.invokeFilters(DefaultAsyncExecutor.java:171)
	at com.sun.grizzly.arp.DefaultAsyncExecutor.interrupt(DefaultAsyncExecutor.java:143)
	at com.sun.grizzly.arp.AsyncProcessorTask.doTask(AsyncProcessorTask.java:102)
	at com.sun.grizzly.http.TaskBase.run(TaskBase.java:193)
	at com.sun.grizzly.http.TaskBase.execute(TaskBase.java:175)
	at com.sun.grizzly.arp.DefaultAsyncHandler.handle(DefaultAsyncHandler.java:145)
	at com.sun.grizzly.arp.AsyncProtocolFilter.execute(AsyncProtocolFilter.java:210)
	at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
	at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
	at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
	at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
	at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
	at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
	at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
	at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
	at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
	at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.NullPointerException
	at br.com.rpctv.siseng.entidade.Unidade.toString(Unidade.java:451)
	at java.lang.String.valueOf(String.java:2854)
	at java.lang.StringBuilder.append(StringBuilder.java:128)
	at org.hibernate.event.def.DefaultMergeEventListener.getTransientCopyCache(DefaultMergeEventListener.java:133)
	at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:90)
	at org.hibernate.impl.SessionImpl.fireMerge(SessionImpl.java:867)
	at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:851)
	at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:855)
	at org.hibernate.ejb.AbstractEntityManagerImpl.merge(AbstractEntityManagerImpl.java:686)
	at com.sun.enterprise.container.common.impl.EntityManagerWrapper.merge(EntityManagerWrapper.java:286)
	at br.com.rpctv.siseng.Facade.AbstractFacade.salvar(AbstractFacade.java:37)
	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:601)
	at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1052)
	at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1124)
	at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5388)
	at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:619)
	at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)
	at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:571)
	at org.jboss.weld.ejb.SessionBeanInterceptor.aroundInvoke(SessionBeanInterceptor.java:42)
	at sun.reflect.GeneratedMethodAccessor179.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:601)
	at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:861)
	at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)
	at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:571)
	at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:162)
	at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:144)
	at sun.reflect.GeneratedMethodAccessor178.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:601)
	at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:861)
	at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)
	at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:370)
	at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:5360)
	at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:5348)
	at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:214)
	... 88 more

INFO: ERROR: javax.ejb.EJBException

ao clickar em at br.com.rpctv.siseng.entidade.Unidade.toString(Unidade.java:451)

ele vai para a seguinte parte do meu código:


@Override
    public String toString() {//MAIS ESPECIFICO AQUI
        return id.toString();
    }
    
    public String nomeUnidade(){
    return unidade;
    }

e não sei como arrumar isso, agradeço desde já.

Problema resolvido, passando unidade null para a entidade.