private static MessageSender messageSender;

//...

public static MessageSender getMessageSender(){
    return messageSender;
}

<bean id="context" class="org.abc.Context">

   <property name="messageSender"><ref bean="mailMessageSender"/></property>
</bean>

public abstract class MailMessageSender{

   protected abstract Session createSession();

   //using createSession() somewhere in this class
}

<bean id="session" class="javax.mail.Session" scope="prototype" />

<bean id="mailMessageSender" class="org.abc.MailMessageSender">
   <lookup-method name="createSession" bean="session"/>
</bean>