Model

package pl.selfimproveit.model;

import java.io.Serializable;
import java.util.Comparator;

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

@Entity
@Table(name = "USER", uniqueConstraints =   @UniqueConstraint(columnNames = {"NAME","SURNAME"}))

public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @Column(name = "UserID")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

    @Column(name = "NAME")
    private String firstName;

    @Column(name = "SURNAME")
    private String lastName;

    @Override
    public String toString() {
        return "User [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + "]";
    }
// getters & setters ommited
}