CREATE TABLE Rechte
    (
    r_id INT GENERATED BY DEFAULT AS IDENTITY(START WITH 0) NOT NULL PRIMARY KEY,
    rechteBEZ VARCHAR(50)
    );


CREATE TABLE User
    (
    u_id INT GENERATED BY DEFAULT AS IDENTITY(START WITH 0) NOT NULL PRIMARY KEY,
    RechteID INTEGER,
    username VARCHAR(50),
    passwort VARCHAR(50),
    nachname VARCHAR(50),
    vorname VARCHAR(50),
    email VARCHAR(50),
    geburtsdatum VARCHAR(10),
    geschlecht CHAR(1),
    avatar VARCHAR(100),
    adresse VARCHAR(50),
    plz INTEGER,
    ort VARCHAR(50),
    telefon VARCHAR(20),
    frage VARCHAR(100),
    antwort VARCHAR(50),
    kamera VARCHAR(50),
    vorlieben VARCHAR(200),
    motive VARCHAR(200),
    FOREIGN KEY(RechteID) REFERENCES Rechte(R_ID)
    );

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">




<hibernate-mapping package="main.java.org.hibernate.DB">


	<class name="User" table="User">
		<id name="id" type="int" column="u_id">
			<generator class="native" />
		</id>


		<property name="username" />
		<property name="passwort" />
		<property name="nachname" />
		<property name="vorname" />
		<property name="email" />
		<property name="geburtsdatum" />
		<property name="geschlecht" />
		<property name="avatar" />
		<property name="adresse" />
		<property name="plz" />
		<property name="ort" />
		<property name="telefon" />
		<property name="frage" />
		<property name="antwort" />
		<property name="vorlieben" />
		<property name="kamera" />
		<property name="motive" />


		<many-to-one name="rechte" class="Rechte" column="RechteID" not-null="true" />


	</class>
</hibernate-mapping>

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">


<hibernate-mapping package="main.java.org.hibernate.DB">


    <class name="Rechte" table="Rechte">
        <id name="id" type="int" column="r_id">
            <generator class="native"/>
        </id>
        <property name="rechteBEZ"/>


        <set name="users" inverse="true">
            <key column="RechteID" not-null="true" />
            <one-to-many class="User"/>
        </set>

    </class>


</hibernate-mapping>

public void save(User user) throws RuntimeException
	{
		try
		{
			Session session = HibernateUtil.getSessionFactory().getCurrentSession();
			session.beginTransaction();


			session.saveOrUpdate(user);
			session.getTransaction().commit();
		}
		catch (Exception e)
		{
			HibernateUtil.getSessionFactory().getCurrentSession().getTransaction().rollback();


			throw new RuntimeException(e.getMessage());
		}
		finally
		{
			// HibernateSessionFactory.closeSession();
		}




	public List<?> getAll() throws RuntimeException
	{
		List list = null;
		try {
			Session session = HibernateUtil.getSessionFactory().getCurrentSession();
			session.beginTransaction();
			list = session.createQuery("from " + User.class.getName()).list();
			session.getTransaction().commit();
		} catch (HibernateException e) {
			// throw new RuntimeException(e.getMessage());
			throw e;
		} finally {
			// HibernateSessionFactory.closeSession();
		}
		return list;
	}

private static void testRechte()
	{
		r = new RechteHibernate();
		Rechte rechte = new Rechte();


		List recht = r.getAll();
		for (int i = 0; i < recht.size(); i++)
		{
			Rechte re = (Rechte) recht.get(i);


			if (re.getRechteBEZ().equals("Admin"))
			{
				rechte = re;
			}
		}


		User u = new User();
		u.setRechte(rechte);
		rechte.getUsers().add(u);
		UserHibernate uh = new UserHibernate();
		uh.save(u);
	}

private static void listUsers()
	{
		List users = u.getAll();
		for (int i = 0; i < users.size(); i++)
		{
			User user = (User) users.get(i);
			System.out.println("Username: " + user.getUsername());
			System.out.println(user.getRechte());
		}

	}

Initial SessionFactory creation failed.org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer]
Exception in thread "main" java.lang.ExceptionInInitializerError
	at main.java.org.hibernate.util.HibernateUtil.buildSessionFactory(HibernateUtil.java:18)
	at main.java.org.hibernate.util.HibernateUtil.<clinit>(HibernateUtil.java:8)
	at Hibernate.RechteHibernate.getAll(RechteHibernate.java:108)
	at Tests.TestRecht.listRechte(TestRecht.java:79)
	at Tests.TestRecht.main(TestRecht.java:22)
Caused by: org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer]
	at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:110)
	at org.hibernate.tuple.entity.EntityTuplizerFactory.constructDefaultTuplizer(EntityTuplizerFactory.java:135)
	at org.hibernate.tuple.entity.EntityEntityModeToTuplizerMapping.<init>(EntityEntityModeToTuplizerMapping.java:80)
	at org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:323)
	at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:456)
	at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:131)
	at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:84)
	at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:267)
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1341)
	at main.java.org.hibernate.util.HibernateUtil.buildSessionFactory(HibernateUtil.java:13)
	... 4 more
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
	at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:107)
	... 13 more
Caused by: org.hibernate.PropertyNotFoundException: Could not find a getter for recht in class main.java.org.hibernate.DB.User
	at org.hibernate.property.BasicPropertyAccessor.createGetter(BasicPropertyAccessor.java:306)
	at org.hibernate.property.BasicPropertyAccessor.getGetter(BasicPropertyAccessor.java:299)
	at org.hibernate.mapping.Property.getGetter(Property.java:294)
	at org.hibernate.tuple.entity.PojoEntityTuplizer.buildPropertyGetter(PojoEntityTuplizer.java:300)
	at org.hibernate.tuple.entity.AbstractEntityTuplizer.<init>(AbstractEntityTuplizer.java:141)
	at org.hibernate.tuple.entity.PojoEntityTuplizer.<init>(PojoEntityTuplizer.java:78)
	... 18 more

public class User implements Serializable
{
	private static final long	serialVersionUID	= -6829822767175518387L;
	private String				username;
	private String				passwort;
	private String				nachname;
	private String				vorname;
	private String				email;
	private String				geburtsdatum;
	private char				geschlecht;
	private String				avatar;
	private String				adresse;
	private int					plz;
	private String				ort;
	private String				telefon;
	private String				frage;
	private String				antwort;
	private String				kamera;
	private String				vorlieben;
	private String				motive;
	private int					u_id;


	private Rechte rechte;

	public Rechte getRechte()
	{
		return rechte;
	}


	public void setRechte(Rechte rechte)
	{
		this.rechte = rechte;
	}




.........

package main.java.org.hibernate.DB;


import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;


public class Rechte implements Serializable
{


	private static final long	serialVersionUID	= 3798844407433161889L;


	private String				rechteBEZ;
	private int					r_id;


	private Set					users				= null;


	public Rechte()
	{
		users = new HashSet();
	}


	public Set getUsers()
	{
		return users;
	}


	public void setUsers(Set users)
	{
		this.users = users;
	}


	public int getId()
	{
		return r_id;
	}


	public void setId(int r_id)
	{
		this.r_id = r_id;
	}


	public String getRechteBEZ()
	{
		return rechteBEZ;
	}


	public void setRechteBEZ(String rechteBEZ)
	{
		this.rechteBEZ = rechteBEZ;
	}


	public String toString()
	{
		return this.rechteBEZ + " " + this.r_id;
	}
}