private static final EntityManagerFactory ENTITY_FACTORY_HOLDER = Persistence.createEntityManagerFactory("LOCAL_PERSISTENCE");

	public static int insertUser(UsersBean bean) {
		int ret = -1;

		EntityManager entityManager = ENTITY_FACTORY_HOLDER.createEntityManager();
		EntityTransaction tr = null;
		try {
			tr = entityManager.getTransaction();
			tr.begin();
			entityManager.persist(bean);
			tr.commit();
		} finally {
			if (tr.isActive()) {
				try {
					tr.rollback();
					return -1;
				} catch (Exception e) {
					System.out.println("Error rolling back transaction" + e.getMessage());
					return -1;
				}
			}
		}

		return ret;
	}




<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
             http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
  version="2.1">

  <persistence-unit name="LOCAL_PERSISTENCE">
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

    <properties>
      <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" />
      <property name="javax.persistence.jdbc.url" value="jdbc:postgresql://localhost:5432/postgres?useUnicode=true&amp;characterEncoding=Cp1251" />
      <property name="javax.persistence.jdbc.user" value="postgres" />
      <property name="javax.persistence.jdbc.password" value="12345" />
      <property name="hibernate.show_sql" value="true" />
      <property name="hibernate.hbm2ddl.auto" value="update" />
    </properties>

  </persistence-unit>
</persistence>


package my.curs.hospital;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "users_curs")
public class UsersBean implements Serializable  {
	public UsersBean() {
	}

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Column(name = "user_id")
	int user_id;

	@Column(name = "user_name")
	String user_name;

	@Column(name = "password")
	String password;

	@Column(name = "e_mail")
	String e_mail;

	@Column(name = "role_id")
	int role_id;

	public int getUser_id() {
		return user_id;
	}

	public void setUser_id(int user_id) {
		System.out.println("Call setUser_id " + user_id );
		this.user_id = user_id;
	}

	public String getUser_name() {
		return user_name;
	}

	public void setUser_name(String user_name) {
		this.user_name = user_name;
	}

	public String getPassword() {
		return password;
	}

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

	public String getE_mail() {
		return e_mail;
	}

	public void setE_mail(String e_mail) {
		this.e_mail = e_mail;
	}

	public int getRole_id() {
		return role_id;
	}

	public void setRole_id(int role_id) {
		this.role_id = role_id;
	}

	@Override
    public String toString() {
        return user_id + "\t" + user_name + "\t" + password + "\t" + e_mail + "\t" + role_id;
    }
}