// default package
// Generated Dec 1, 2006 11:13:24 PM by Hibernate Tools 3.2.0.beta8

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

import org.hibernate.annotations.GenericGenerator;

/**
* User generated by hbm2java
*/
@Entity
@Table(name = "User", catalog = "jpa", uniqueConstraints = {})
public class User implements java.io.Serializable {

    // Fields

    /**
     *
     */
    private static final long serialVersionUID = 4832158639325710373L;

    private String id;

    private String login;

    private String passwd;

    private Set<Role> roles = new HashSet<Role>(0);

    // Constructors

    /** default constructor */
    public User() {
    }

    /** minimal constructor */
    public User(String id, String login, String passwd) {
        this.id = id;
        this.login = login;
        this.passwd = passwd;
    }

    /** full constructor */
    public User(String id, String login, String passwd, Set<Role> roles) {
        this.id = id;
        this.login = login;
        this.passwd = passwd;
        this.roles = roles;
    }

    // Property accessors
    @Id
    @GeneratedValue(generator = "system-uuid")
    @GenericGenerator(name = "system-uuid", strategy = "uuid")
    @Column(name = "id", unique = true, nullable = false, insertable = true, updatable = true, length = 32)
    public String getId() {
        return this.id;
    }

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

    @Column(name = "login", unique = false, nullable = false, insertable = true, updatable = true, length = 32)
    public String getLogin() {
        return this.login;
    }

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

    @Column(name = "passwd", unique = false, nullable = false, insertable = true, updatable = true, length = 32)
    public String getPasswd() {
        return this.passwd;
    }

    public void setPasswd(String passwd) {
        this.passwd = passwd;
    }

    @ManyToMany(cascade = { CascadeType.ALL }, fetch = FetchType.LAZY)
    @JoinTable(name = "UserRole", joinColumns = @JoinColumn(name = "userid", referencedColumnName = "id"), inverseJoinColumns = @JoinColumn(name = "roleid", referencedColumnName = "id"))
    public Set<Role> getRoles() {
        return this.roles;
    }

    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }

    @Override
    public boolean equals(Object o) {
        if (o == this) {
            return true;
        }
        if (!(o instanceof User)) {
            return false;
        }
        return this.login.equals(((User) o).login);
    }

    public int hashCode() {
        return 0;
    }
}

// default package
// Generated Dec 1, 2006 11:13:24 PM by Hibernate Tools 3.2.0.beta8

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

import org.hibernate.annotations.GenericGenerator;

/**
* Role generated by hbm2java
*/
@Entity
@Table(name = "Role", catalog = "jpa", uniqueConstraints = {})
public class Role implements java.io.Serializable {

    // Fields

    /**
     *
     */
    private static final long serialVersionUID = -8599860702857703898L;

    private String id;

    private String role;

    private Set<User> users = new HashSet<User>(0);

    // Constructors

    /** default constructor */
    public Role() {
    }

    /** minimal constructor */
    public Role(String id, String role) {
        this.id = id;
        this.role = role;
    }

    /** full constructor */
    public Role(String id, String role, Set<User> users) {
        this.id = id;
        this.role = role;
        this.users = users;
    }

    // Property accessors
    @Id
    @GeneratedValue(generator = "system-uuid")
    @GenericGenerator(name = "system-uuid", strategy = "uuid")
    @Column(name = "id", unique = true, nullable = false, insertable = true, updatable = true, length = 32)
    public String getId() {
        return this.id;
    }

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

    @Column(name = "role", unique = false, nullable = false, insertable = true, updatable = true, length = 32)
    public String getRole() {
        return this.role;
    }

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

    @ManyToMany(fetch = FetchType.LAZY, mappedBy = "roles")
    public Set<User> getUsers() {
        return this.users;
    }

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

    @Override
    public boolean equals(Object o) {
        if (o == this) {
            return true;
        }
        if (!(o instanceof Role)) {
            return false;
        }
        return this.role.equals(((Role) o).role);
    }

    public int hashCode() {
        return 0;
    }

}

...
    public void testUpdateUser() throws Exception {
        User user = userDao.findById("402881830f4e6643010f4e664d1a0001");
        Role role = user.getRoles().iterator().next();
        role.getUsers().remove(user);
        user.getRoles().remove(role);
        userDao.merge(user);
    }
...