<hibernate-configuration>
        <session-factory>
            <property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
            <property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
            <property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/animal-clinic</property>
            <property name="hibernate.connection.username">postgres</property>
            <property name="hibernate.connection.password">pass</property>

            <property name="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProvider</property>
            <property name="hibernate.c3p0.min_size">7</property>
            <property name="hibernate.c3p0.max_size">53</property>
            <property name="hibernate.c3p0.timeout">100</property>
            <property name="hibernate.c3p0.max_statements">50</property>
            <property name="hibernate.c3p0.idle_test_period">1000</property>
            <property name="hibernate.c3p0.validate">true</property>

            <!-- List of XML mapping files -->
            <mapping resource="ru/lesson/models/users/Role.hbm.xml"/>
            <mapping resource="ru/lesson/models/users/User.hbm.xml"/>
            <mapping resource="ru/lesson/models/users/Message.hbm.xml"/>
        </session-factory>
    </hibernate-configuration>

<hibernate-mapping>
<class name="ru.lesson.models.users.User" table="users">
    <meta attribute="class-description">
        This class contains the user detail.
    </meta>
    <id name="id" type="int" column="uid">
        <generator class="identity"/>
    </id>
    <property name="login" column="login" type="string"/>
    <property name="email" column="email" type="string"/>
    <property name="password" column="password" type="string"/>
    <property name="name" column="name" type="string"/>
    <property name="surname" column="surname" type="string"/>
    <property name="fullname" column="fullname" type="string"/>
    <property name="sex" column="sex" type="string"/>
    <property name="phone_number" column="phone_number" type="string"/>
    <property name="city" column="city" type="string"/>
    <many-to-one name="role" lazy="false" column="role_id" class="ru.lesson.models.users.Role" cascade="save-update"/>
    <bag name="messages" table="messages" lazy="false" inverse="true" cascade="all">
        <key column="user_id" not-null="true"/>
        <one-to-many class="ru.lesson.models.users.Message"/>
    </bag>
</class>
</hibernate-mapping>

<hibernate-mapping>
    <class name="ru.lesson.models.users.Message" table="messages">
        <meta attribute="class-description">
            This class contains the message of user.
        </meta>
        <id name="id" type="int" column="uid">
            <generator class="identity"/>
        </id>
        <many-to-one name="user" column="user_id" class="ru.lesson.models.users.User" cascade="all" insert="false" update="false"/>
        <many-to-one name="sender" column="sender_id" class="ru.lesson.models.users.User" cascade="all" insert="false" update="false"/>
        <property name="text" column="text" type="string"/>
    </class>
</hibernate-mapping>

<hibernate-mapping>
    <class name="ru.lesson.models.users.Role" table="roles">
        <meta attribute="class-description">
            This class contains the role detail.
        </meta>
        <id name="id" type="int" column="uid">
            <generator class="identity"/>
        </id>
        <property name="name" column="name" type="string"/>
    </class>
</hibernate-mapping>

package ru.lesson.models.users;

import java.util.*;

public class User extends Base{
    private String login;
    private String email;
    private String password;
    private String name;
    private String surname;
    private String fullname;
    private String sex;
    private String phone_number;
    private String city;
    private Role role;
    private List<Message> messages = new ArrayList<Message>();

    public User(){}

    public User(int id, String login, String email, String password, String name, String surname,
                String sex, String phone_number, String city){
        this.id = id;
        this.login = login;
        this.email = email;
        this.password = password;
        this.name = name;
        this.surname = surname;
        this.sex = sex;
        this.phone_number = phone_number;
        this.city = city;
        this.fullname = name + " " + surname;
    }

    public List<Message> getMessages() {
        return messages;
    }

    public void setMessages(List<Message> messages) {
        this.messages = messages;
    }

    public String getLogin() {
        return login;
    }

    public void setLogin(String login) {
        this.login = login;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSurname() {
        return surname;
    }

    public void setSurname(String surname) {
        this.surname = surname;
    }

    public String getFullname() {
        return fullname;
    }

    public void setFullname(String fullname) {
        this.fullname = fullname;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getPhone_number() {
        return phone_number;
    }

    public void setPhone_number(String phone_number) {
        this.phone_number = phone_number;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public Role getRole() {
        return role;
    }

    public void setRole(Role role) {
        this.role = role;
    }

    @Override
    public String toString() {
        return "User{" +
                "login='" + login + ''' +
                ", email='" + email + ''' +
                ", password='" + password + ''' +
                ", name='" + name + ''' +
                ", surname='" + surname + ''' +
                ", fullname='" + fullname + ''' +
                ", sex='" + sex + ''' +
                ", phone_number='" + phone_number + ''' +
                ", city='" + city + ''' +
                ", role=" + role +
                ", messages=" + messages +
                '}';
    }
}

package ru.lesson.models.users;

public class Message extends Base {
    private User user;
    private User sender;
    private String text;

    public Message(){}

    public Message(int id, User userToSend, User sender, String textMessage){
        this.user = userToSend;
        this.sender = sender;
        this.text = textMessage;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public User getSender() {
        return sender;
    }

    public void setSender(User sender) { this.sender = sender; }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }
}

package ru.lesson.models.users;

public class Role extends Base {
    private String name;

    public Role(){}

    public Role(int id, String name){
        this.id = id;
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

package ru.lesson.models.users;

public abstract class Base {
    protected int id;

    public int getId() {
        return id;
    }

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

package ru.lesson.store;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;

import java.util.ArrayList;
import java.util.List;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import ru.lesson.models.users.Message;
import ru.lesson.models.users.Role;
import ru.lesson.models.users.User;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:spring-context.xml"})
@WebAppConfiguration
public class UserStorageTest {
    @Autowired
    private Storages storage;
    private int id;
    private int idSender;
    private int size;

    @Test
    public void testStorage(){
        try {
            Role role = new Role();
            role.setName("user");
            User user = new User(-1, "sanyaTest", "testYawik@mail.ru", "123456", "Sanya", "Testirovwik", "Man", "095434345", "Kharkov");
            user.setRole(role);
            User sender = new User(-1, "Sender911", "testSender@mail.ru", "123456", "Sanya", "Sender", "Man", "095434345", "Praga");
            sender.setRole(role);
            idSender = storage.userStorage.add(sender);
            id = storage.userStorage.add(user);
            user = storage.userStorage.get(id);
            assertEquals(id, user.getId());
            assertNotNull(user);
            assertEquals("sanyaTest", user.getLogin());
            assertEquals("testYawik@mail.ru", user.getEmail());
            assertEquals("123456", user.getPassword());
            assertEquals("Sanya", user.getName());
            assertEquals("Testirovwik", user.getSurname());
            assertEquals("Man", user.getSex());
            assertEquals("095434345", user.getPhone_number());
            assertEquals("Kharkov", user.getCity());
            size = storage.userStorage.values().size();

            user = new User(id, "sanyaTest1", "testYawik@mail.ru1", "1234561", "Sanya1", "Testirovwik1", "Man1", "0954343451", "Kharkov1");
            user.setRole(role);
            List<Message> messages = new ArrayList<Message>();
            Message message = new Message(-1,user,sender,"textTestJUNIt");
            messages.add(message);
            user.setMessages(messages);
            storage.userStorage.edit(user);
            user = storage.userStorage.get(id);
            assertEquals(1, storage.userStorage.get(id).getMessages().size());
            assertEquals(id, user.getId());
            assertNotNull(user);
            assertEquals("sanyaTest1", user.getLogin());
            assertEquals("testYawik@mail.ru1", user.getEmail());
            assertEquals("1234561", user.getPassword());
            assertEquals("Sanya1", user.getName());
            assertEquals("Testirovwik1", user.getSurname());
            assertEquals("Man1", user.getSex());
            assertEquals("0954343451", user.getPhone_number());
            assertEquals("Kharkov1", user.getCity());

            List<User> list = storage.userStorage.searchByID(id);
            assertNotNull(list.get(0));
            assertEquals(list.get(0).getId(), user.getId());

            user = storage.userStorage.findByAuth("sanyaTest1", "1234561");
            assertNotNull(user);

            list = storage.userStorage.searchByName("Sanya1 Testirovwik1");
            assertNotNull(list.get(0));

            //list = storage.searchByLogin(user.getLogin());
            //assertNotNull(list.get(0));
        }finally{
            /*storage.userStorage.delete(id);
            assertEquals(size-1, storage.userStorage.values().size());*/
        }
    }
}

org.springframework.dao.DataIntegrityViolationException: could not    execute statement; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement

        at org.springframework.orm.hibernate4.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:161)
        at org.springframework.orm.hibernate4.HibernateTemplate.doExecute(HibernateTemplate.java:343)
        at org.springframework.orm.hibernate4.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:308)
        at org.springframework.orm.hibernate4.HibernateTemplate.update(HibernateTemplate.java:644)
        at org.springframework.orm.hibernate4.HibernateTemplate.update(HibernateTemplate.java:639)
        at ru.lesson.store.UserStorage.edit(UserStorage.java:43)
        at ru.lesson.store.UserStorage.edit(UserStorage.java:19)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:497)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
        at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:98)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:262)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
        at com.sun.proxy.$Proxy17.edit(Unknown Source)
        at ru.lesson.store.UserStorageTest.testStorage(UserStorageTest.java:64)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:497)
        at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
        at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
        at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
        at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
        at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
        at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
        at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233)
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)
        at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
        at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
        at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
        at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
        at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
        at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
        at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176)
        at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
        at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
        at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)
        at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:497)
        at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
        Caused by: org.hibernate.exception.ConstraintViolationException: could not execute statement
        at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:129)
        at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
        at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
        at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:112)
        at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:211)
        at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:96)
        at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:58)
        at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3032)
        at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3558)
        at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:98)
        at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:492)
        at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:197)
        at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:181)
        at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:216)
        at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:334)
        at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:289)
        at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:195)
        at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:126)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:209)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:194)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:114)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
        at org.hibernate.internal.SessionImpl.fireSaveOrUpdate(SessionImpl.java:684)
        at org.hibernate.internal.SessionImpl.saveOrUpdate(SessionImpl.java:676)
        at org.hibernate.engine.spi.CascadingActions$5.cascade(CascadingActions.java:235)
        at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:350)
        at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:293)
        at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
        at org.hibernate.engine.internal.Cascade.cascadeCollectionElements(Cascade.java:379)
        at org.hibernate.engine.internal.Cascade.cascadeCollection(Cascade.java:319)
        at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:296)
        at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
        at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:118)
        at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:86)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.cascadeOnUpdate(DefaultSaveOrUpdateEventListener.java:375)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:349)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:244)
        at org.hibernate.event.internal.DefaultUpdateEventListener.performSaveOrUpdate(DefaultUpdateEventListener.java:55)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
        at org.hibernate.internal.SessionImpl.fireUpdate(SessionImpl.java:739)
        at org.hibernate.internal.SessionImpl.update(SessionImpl.java:731)
        at org.hibernate.internal.SessionImpl.update(SessionImpl.java:726)
        at org.springframework.orm.hibernate4.HibernateTemplate$14.doInHibernate(HibernateTemplate.java:648)
        at org.springframework.orm.hibernate4.HibernateTemplate.doExecute(HibernateTemplate.java:340)
        ... 50 more
        Caused by: org.postgresql.util.PSQLException: ОШИБКА: нулевое значение в колонке "user_id" нарушает ограничение NOT NULL
        Подробности: Ошибочная строка содержит (12, textTestJUNIt, null, null).
        at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2103)
        at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1836)
        at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
        at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:512)
        at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:388)
        at org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2Statement.java:334)
        at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:147)
        at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:208)
        ... 89 more