User us = list.get(0);
		us.setClicks(us.getClicks()+1);
		em.merge(us);
		return us;

package model;

import java.io.Serializable;

import javax.persistence.*;

import java.math.BigDecimal;
import java.math.BigInteger;

/**
 * The persistent class for the USERS database table.
 * 
 */
@Entity
@Table(name = "USERS")
@NamedQuery(name = "findUser", query = "SELECT u FROM User u where u.id=:user and u.password=:password")
public class User implements Serializable {
	private static final long serialVersionUID = 1L;

	@Id
	@GeneratedValue(strategy = GenerationType.TABLE)
	private String id;

	private Integer clicks;

	private String password;

	private String sn;

	public User() {
	}

	public String getId() {
		return this.id;
	}

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

	public Integer getClicks() {
		return this.clicks;
	}

	public void setClicks(Integer clicks) {
		this.clicks = clicks;
	}

	public String getPassword() {
		return this.password;
	}

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

	public String getSn() {
		return this.sn;
	}

	public void setSn(String sn) {
		this.sn = sn;
	}

	public String toString() {
		return id + " " + sn + " " + password + " " + clicks;
	}

}