Getting NullPoint Exception when i used UserTransaction.

[peddu007]

Hi I am using EntityManager with JTA Transaction when i used UserTransaction getting Nullpoint Exception...

@Name("sample")

@Scope(ScopeType.CONVERSATION)

public class SampleHome extends EntityHome<Sample> implements Serializable {

   @Resource

    UserTransaction userTx;

     @In

     EntityManager entityManager;

   @Begin(join = true)

    public void create() {

    }

   @Begin(join=true)

   public void userTransaction(){

               userTx.setTransactionTimeout(10 * 60); //getting null point exception

               userTx.begin();//getting null point exception

               getEntityManager().joinTransaction();

                ///coding

                getEntityManager().persist(temp);

                getEntityManager().flush();

   }

component.xml

  <core:init debug="false" jndi-pattern="@jndiPattern@"/>

    <core:manager concurrent-request-timeout="2000"

        conversation-id-parameter="cid" conversation-timeout="120000"

        parent-conversation-id-parameter="pid" />

    <web:hot-deploy-filter url-pattern="/*.mobee" />

    <persistence:entity-manager-factory

        installed="@seamBootstrapsPu@" name="entityManagerFactory"

        persistence-unit-name="mobeeadmin" />

    <persistence:managed-persistence-context

        auto-create="true" entity-manager-factory="@seamEmfRef@" name="entityManager"

        persistence-unit-jndi-name="@puJndiName@" />

        <async:quartz-dispatcher />

    <security:identity authenticate-method="#{authenticator.authenticate}" />

    <web:rewrite-filter view-mapping="*.mobee" />

    <web:multipart-filter create-temp-files="true" max-request-size="28672000" url-pattern="*.seam"/>

    <event type="org.jboss.seam.security.notLoggedIn">

        <action execute="#{redirect.captureCurrentView}" />

    </event>

    <event type="org.jboss.seam.security.loginSuccessful">

        <action execute="#{redirect.returnToCapturedView}" />

    </event>

    <mail:mail-session host="localhost" port="25" />