<?xml version="1.0"?> 
  <persistence xmlns="http://java.sun.com/xml/ns/persistence" 
  	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.0"> 
   
  	<persistence-unit name="Persistence" transaction-type="RESOURCE_LOCAL"> 
   
  		<provider>org.hibernate.ejb.HibernatePersistence</provider> 
   
  		<class>model.business.Project</class> 
  		<class>model.business.Activity</class> 
  		<class>model.business.Worker</class> 
  		<class>model.business.Task</class> 
  		<class>model.business.Assignment</class> 
  		<class>model.business.Skill</class> 
  		 
  		<exclude-unlisted-classes>true</exclude-unlisted-classes> 
   
  		<properties> 
  			<property name="hibernate.dialect" value="org.hibernate.dialect.SQLServer2008Dialect" /> 
  			<property name="connection.driver_class" 
  				value="com.microsoft.sqlserver.jdbc.SQLServerDriver" /> 
  			<property name="connection.url" 
  				value="jdbc:sqlserver://127.0.0.1:1433;databaseName=MyDB;instanceName=MSSQLSERVER;integratedSecurity=false;" /> 
  			<property name="hibernate.connection.username" value="root" /> 
  			<property name="hibernate.connection.password" value="12345678" /> 
  			<property name="hibernate.hbm2dll.auto" value="update" /> 
   
  			<property name="hibernate.hbm2ddl.auto" value="create" /> 
  			<property name="hibernate.show_sql" value="true" /> 
  			<property name="hibernate.format_sql" value="true" /> 
  		</properties> 
  	</persistence-unit> 
  </persistence>

Exception in thread "main" javax.persistence.PersistenceException: [PersistenceUnit: Persistence] Unable to build EntityManagerFactory 
  	at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:924) 
  	at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:899) 
  	at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:59) 
  	at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:63) 
  	at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:47) 
  	at model.dao.TimeResourceManagementDAOFactory.<init>(TimeResourceManagementDAOFactory.java:20) 
  	at model.dao.TimeResourceManagementDAOFactory.getInstance(TimeResourceManagementDAOFactory.java:25) 
  	at view.ProjectTable.<init>(ProjectTable.java:32) 
  	at view.MainScreen.<init>(MainScreen.java:23) 
  	at view.MainScreen.main(MainScreen.java:45) 
  Caused by: org.hibernate.AnnotationException: Illegal attempt to map a non collection as a @OneToMany, @ManyToMany or @CollectionOfElements: model.business.Assignment.listTimeLog 
  	at org.hibernate.cfg.annotations.CollectionBinder.getCollectionBinder(CollectionBinder.java:327) 
  	at org.hibernate.cfg.AnnotationBinder.processElementAnnotations(AnnotationBinder.java:1721) 
  	at org.hibernate.cfg.AnnotationBinder.processIdPropertiesIfNotAlready(AnnotationBinder.java:767) 
  	at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:686) 
  	at org.hibernate.cfg.Configuration$MetadataSourceQueue.processAnnotatedClassesQueue(Configuration.java:3512) 
  	at org.hibernate.cfg.Configuration$MetadataSourceQueue.processMetadata(Configuration.java:3466) 
  	at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1355) 
  	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1756) 
  	at org.hibernate.ejb.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:96) 
  	at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:914) 
  	... 9 more