Erreur java.lang.NullPointerException in jsf managed bean - spring

Question

Hello i have Started a spring jsf project when i run the first page jsf i recived this error:
java.lang.NullPointerException
com.project.formation.bean.StudentBean.addStudent(StudentBean.java:31)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.apache.el.parser.AstValue.invoke(AstValue.java:278)
org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:273)
com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
javax.faces.component.UICommand.broadcast(UICommand.java:315)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
can u help me and thank you !
the problem is in the jsf managed bean exactly in the addStudent() method:
public class StudentBean implements Serializable {
#Autowired
private StudentService studentService;
private Student student;
public StudentBean() {
student = new Student();
}
public void addStudent() {
studentService.add(student);//line 31
student=new Student();
}
public List<Student> getStudentList() {
return studentService.findAll();
}
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
}
My Dao bean code is :
public class StudentDaoImpl implements StudentDao {
#PersistenceContext
private EntityManager em;
#Override
public void add(Student student) {
em.persist(student);
}
#SuppressWarnings("unchecked")
#Override
public List<Student> findAll() {
Query query=em.createQuery("select s from Student s");
return query.getResultList();
}
}
and the complete spring xml file configuration: applicationContext.xml is :
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">
<!-- bean of data source -->
<bean id="datasource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://localhost:3306/Student"></property>
<property name="username" value="root"></property>
<property name="password" value=""></property>
</bean>
<!-- bean of persistence manager -->
<bean id="persistenceUnitManager" class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
<property name="defaultDataSource" ref="datasource"></property>
<property name="persistenceXmlLocations">
<list>
<value>classpath*:META-INF/persistence.xml</value>
</list>
</property>
</bean>
<!-- bean definition entityManagerFactory -->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitManager" ref="persistenceUnitManager"></property>
<property name="persistenceUnitName" value="UP_STUDENT"></property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory"></property>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<context:annotation-config></context:annotation-config>
<bean id="studentDao" class="com.project.formation.dao.StudentDaoImpl"/>
<bean id="studentService" class="com.project.formation.service.StudentServiceImpl"/>
</beans>

Answer 1

I suspect your StudentService is not autowired and is null, check to make sure it is annotated with #Service or #component so it is known to spring context.
generally you should mark it required=true if your app requires a bean to function.

Answer 2

you dont have a getter and setter for your student service in your StudenBean