[Hibernate]Error: entity class not found:

I get tired of this for a long time. I do not know what caused this error. Here are my files:

Uzytkownik.hbm.xml

    <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
                                   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
 <class name="Uzytkownik" table="uzytkownicy">
  <id column="id" name="id" type="int"/>
  <property column="login" generated="never" lazy="false" name="login" type="string"/>
  <property column="haslo" generated="never" lazy="false" name="haslo" type="string"/>
 </class>
</hibernate-mapping>

hibernate.cfg.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
                                         "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
 <session-factory name="">
  <property name="hibernate.connection.driver_class">org.gjt.mm.mysql.Driver</property>
  <property name="hibernate.connection.password">root</property>
  <property name="hibernate.connection.url">jdbc:mysql://localhost/sprawozdania</property>
  <property name="hibernate.connection.username">root</property>
  <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
  <mapping resource="com/vaannila/uzytkownik/Uzytkownik.hbm.xml"/>
 </session-factory>
</hibernate-configuration>

I use mysql 5.5.

I get the following error:

 Exception in thread "main" java.lang.ExceptionInInitializerError
    at com.vaannila.util.HibernateUtil.<clinit>(HibernateUtil.java:14)
    at com.vaannila.uzytkownik.Main.saveUzyt(Main.java:22)
    at com.vaannila.uzytkownik