:: Liferay. PermissionChecker not initialized

Un error que se producía en un portlet desarrollado en Liferay 6.2, a la hora de consultar un campo personalizado, era el siguiente: "PermissionChecker not initialized"

com.liferay.portal.kernel.messaging.MessageListenerException: java.lang.RuntimeException: com.liferay.portal.security.auth.PrincipalException: PermissionChecker not initialized
        at com.liferay.portal.kernel.scheduler.messaging.SchedulerEventMessageListenerWrapper.receive(SchedulerEventMessageListenerWrapper.java:86)
        at com.liferay.portal.kernel.messaging.InvokerMessageListener.receive(InvokerMessageListener.java:72)
        at com.liferay.portal.kernel.messaging.ParallelDestination$1.run(ParallelDestination.java:71)
        at com.liferay.portal.kernel.concurrent.ThreadPoolExecutor$WorkerTask._runTask(ThreadPoolExecutor.java:682)
        at com.liferay.portal.kernel.concurrent.ThreadPoolExecutor$WorkerTask.run(ThreadPoolExecutor.java:593)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: com.liferay.portal.security.auth.PrincipalException: PermissionChecker not initialized
        at com.liferay.portlet.expando.model.impl.ExpandoBridgeImpl.getAttribute(ExpandoBridgeImpl.java:219)
        at com.liferay.portlet.expando.model.impl.ExpandoBridgeImpl.getAttribute(ExpandoBridgeImpl.java:199)
        at sun.reflect.GeneratedMethodAccessor6456.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at com.liferay.portal.kernel.bean.ClassLoaderBeanHandler.invoke(ClassLoaderBeanHandler.java:67)
        at com.sun.proxy.$Proxy1399.receive(Unknown Source)
        at com.liferay.portal.kernel.scheduler.messaging.SchedulerEventMessageListenerWrapper.receive(SchedulerEventMessageListenerWrapper.java:77)
        ... 5 more
Caused by: com.liferay.portal.security.auth.PrincipalException: PermissionChecker not initialized
        at com.liferay.portal.service.BaseServiceImpl.getPermissionChecker(BaseServiceImpl.java:82)
        at com.liferay.portlet.expando.service.impl.ExpandoValueServiceImpl.getData(ExpandoValueServiceImpl.java:125)
        at sun.reflect.GeneratedMethodAccessor1874.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at com.liferay.portal.spring.aop.ServiceBeanMethodInvocation.proceed(ServiceBeanMethodInvocation.java:115)
        at com.liferay.portal.spring.transaction.DefaultTransactionExecutor.execute(DefaultTransactionExecutor.java:62)
        at com.liferay.portal.spring.transaction.TransactionInterceptor.invoke(TransactionInterceptor.java:51)
        at com.liferay.portal.spring.aop.ServiceBeanMethodInvocation.proceed(ServiceBeanMethodInvocation.java:111)
        at com.liferay.portal.spring.aop.ChainableMethodAdvice.invoke(ChainableMethodAdvice.java:56)
        at com.liferay.portal.spring.aop.ServiceBeanMethodInvocation.proceed(ServiceBeanMethodInvocation.java:111)
        at com.liferay.portal.spring.aop.ChainableMethodAdvice.invoke(ChainableMethodAdvice.java:56)
        at com.liferay.portal.spring.aop.ServiceBeanMethodInvocation.proceed(ServiceBeanMethodInvocation.java:111)
        at com.liferay.portal.spring.aop.ServiceBeanAopProxy.invoke(ServiceBeanAopProxy.java:175)
        at com.sun.proxy.$Proxy228.getData(Unknown Source)
        at com.liferay.portlet.expando.service.ExpandoValueServiceUtil.getData(ExpandoValueServiceUtil.java:107)
        at com.liferay.portlet.expando.model.impl.ExpandoBridgeImpl.getAttribute(ExpandoBridgeImpl.java:208)
        ... 14 more

Este error se lanzaba a la hora de consultar el valor del campo personalizado desde una tarea programada:

user.getExpandoBridge().getAttribute("nombre-del-campo-personalizado");

La solución a este problema, documentado en los foros de Liferay fue el siguiente:

try{
//Backup del permiso actual
PermissionChecker permissionCheckerBackup= PermissionThreadLocal.getPermissionChecker();

//Recupera el valor del del campo personalizado
PrincipalThreadLocal.setName(user.getUserId());
PermissionChecker permissionChecker;
permissionChecker = PermissionCheckerFactoryUtil.create(user);
PermissionThreadLocal.setPermissionChecker(permissionChecker);

campoPersonalizado=(boolean) user.getExpandoBridge().getAttribute("nombre-del-campo-personalizado");

//Restablece el permiso inicial
PermissionThreadLocal.setPermissionChecker(permissionCheckerBackup);
}catch(Exception ex){
ex.printStackTrace();
}

Más información: https://liferay.dev/forums/-/message_boards/message/48763277