Estou trabalhando em um projeto com o Spring, por que continuo recebendo o seguinte erro?

javax.validation.UnexpectedTypeException:
Não foi possível encontrar nenhum validador para o tipo: java.lang.Integer

Aqui está o meu código:

package com.s2rsolutions.model;

import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.validation.constraints.Size;

import org.hibernate.validator.constraints.NotEmpty;

@Entity
@Table(name = "sales")
public class Sales {

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "ttl_d_sls_lst_mth", nullable = false)
    private Integer ttl_d_sls_lst_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "ttl_d_sls_6_mth", nullable = false)
    private Integer ttl_d_sls_6_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "ttl_d_sls_mtht", nullable = false)
    private Integer ttl_d_sls_mtht;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "ttl_s_sls_lst_mth", nullable = false)
    private Integer ttl_s_sls_lst_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "ttl_s_sls_6_mth", nullable = false)
    private Integer ttl_s_sls_6_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "ttl_s_sls_mtht", nullable = false)
    private Integer ttl_s_sls_mtht;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "nw_lst_mth", nullable = false)
    private Integer nw_lst_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "nw_6_mth", nullable = false)
    private Integer nw_6_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "nw_mtht", nullable = false)
    private Integer nw_mtht;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "usd_lst_mth", nullable = false)
    private Integer usd_lst_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "usd_6_mth", nullable = false)
    private Integer usd_6_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "usd_mtht", nullable = false)
    private Integer usd_mtht;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "grss_prt_pvnr_lst_mth", nullable = false)
    private Integer grss_prt_pvnr_lst_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "grss_prt_pvnr_6_mth", nullable = false)
    private Integer grss_prt_pvnr_6_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "grss_prt_pvnr_mtht", nullable = false)
    private Integer grss_prt_pvnr_mtht;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "grss_prt_pvur_lst_mth", nullable = false)
    private Integer grss_prt_pvur_lst_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "grss_prt_pvur_6_mth", nullable = false)
    private Integer grss_prt_pvur_6_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "grss_prt_pvur_mtht", nullable = false)
    private Integer grss_prt_pvur_mtht;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "shwrm_tffic_lst_mth", nullable = false)
    private Integer shwrm_tffic_lst_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "shwrm_tffic_6_mth", nullable = false)
    private Integer shwrm_tffic_6_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "shwrm_tffic_mtht", nullable = false)
    private Integer shwrm_tffic_mtht;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "shwrm_clsng_lst_mth", nullable = false)
    private Integer shwrm_clsng_lst_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "shwrm_clsng_6_mth", nullable = false)
    private Integer shwrm_clsng_6_mth;

    @NotEmpty(message = "The above field must not be blank.")
    @Column(name = "shwrm_clsng_mtht", nullable = false)
    private Integer shwrm_clsng_mtht;

    @Column(name = "date_added")
    private Date addedDate;


    public Integer getTtl_d_sls_lst_mth() {
        return ttl_d_sls_lst_mth;
    }

    public void setTtl_d_sls_lst_mth(Integer ttl_d_sls_lst_mth) {
        this.ttl_d_sls_lst_mth = ttl_d_sls_lst_mth;
    }

    public Integer getTtl_d_sls_6_mth() {
        return ttl_d_sls_6_mth;
    }

    public void setTtl_d_sls_6_mth(Integer ttl_d_sls_6_mth) {
        this.ttl_d_sls_6_mth = ttl_d_sls_6_mth;
    }

    public Integer getTtl_d_sls_mtht() {
        return ttl_d_sls_mtht;
    }

    public void setTtl_d_sls_mtht(Integer ttl_d_sls_mtht) {
        this.ttl_d_sls_mtht = ttl_d_sls_mtht;
    }

    public Integer getTtl_s_sls_lst_mth() {
        return ttl_s_sls_lst_mth;
    }

    public void setTtl_s_sls_lst_mth(Integer ttl_s_sls_lst_mth) {
        this.ttl_s_sls_lst_mth = ttl_s_sls_lst_mth;
    }

    public Integer getTtl_s_sls_6_mth() {
        return ttl_s_sls_6_mth;
    }

    public void setTtl_s_sls_6_mth(Integer ttl_s_sls_6_mth) {
        this.ttl_s_sls_6_mth = ttl_s_sls_6_mth;
    }

    public Integer getTtl_s_sls_mtht() {
        return ttl_s_sls_mtht;
    }

    public void setTtl_s_sls_mtht(Integer ttl_s_sls_mtht) {
        this.ttl_s_sls_mtht = ttl_s_sls_mtht;
    }

    public Integer getNw_lst_mth() {
        return nw_lst_mth;
    }

    public void setNw_lst_mth(Integer nw_lst_mth) {
        this.nw_lst_mth = nw_lst_mth;
    }

    public Integer getNw_6_mth() {
        return nw_6_mth;
    }

    public void setNw_6_mth(Integer nw_6_mth) {
        this.nw_6_mth = nw_6_mth;
    }

    public Integer getNw_mtht() {
        return nw_mtht;
    }

    public void setNw_mtht(Integer nw_mtht) {
        this.nw_mtht = nw_mtht;
    }

    public Integer getUsd_lst_mth() {
        return usd_lst_mth;
    }

    public void setUsd_lst_mth(Integer usd_lst_mth) {
        this.usd_lst_mth = usd_lst_mth;
    }

    public Integer getUsd_6_mth() {
        return usd_6_mth;
    }

    public void setUsd_6_mth(Integer usd_6_mth) {
        this.usd_6_mth = usd_6_mth;
    }

    public Integer getUsd_mtht() {
        return usd_mtht;
    }

    public void setUsd_mtht(Integer usd_mtht) {
        this.usd_mtht = usd_mtht;
    }

    public Integer getGrss_prt_pvnr_lst_mth() {
        return grss_prt_pvnr_lst_mth;
    }

    public void setGrss_prt_pvnr_lst_mth(Integer grss_prt_pvnr_lst_mth) {
        this.grss_prt_pvnr_lst_mth = grss_prt_pvnr_lst_mth;
    }

    public Integer getGrss_prt_pvnr_6_mth() {
        return grss_prt_pvnr_6_mth;
    }

    public void setGrss_prt_pvnr_6_mth(Integer grss_prt_pvnr_6_mth) {
        this.grss_prt_pvnr_6_mth = grss_prt_pvnr_6_mth;
    }

    public Integer getGrss_prt_pvnr_mtht() {
        return grss_prt_pvnr_mtht;
    }

    public void setGrss_prt_pvnr_mtht(Integer grss_prt_pvnr_mtht) {
        this.grss_prt_pvnr_mtht = grss_prt_pvnr_mtht;
    }

    public Integer getGrss_prt_pvur_lst_mth() {
        return grss_prt_pvur_lst_mth;
    }

    public void setGrss_prt_pvur_lst_mth(Integer grss_prt_pvur_lst_mth) {
        this.grss_prt_pvur_lst_mth = grss_prt_pvur_lst_mth;
    }

    public Integer getGrss_prt_pvur_6_mth() {
        return grss_prt_pvur_6_mth;
    }

    public void setGrss_prt_pvur_6_mth(Integer grss_prt_pvur_6_mth) {
        this.grss_prt_pvur_6_mth = grss_prt_pvur_6_mth;
    }

    public Integer getGrss_prt_pvur_mtht() {
        return grss_prt_pvur_mtht;
    }

    public void setGrss_prt_pvur_mtht(Integer grss_prt_pvur_mtht) {
        this.grss_prt_pvur_mtht = grss_prt_pvur_mtht;
    }

    public Integer getShwrm_tffic_lst_mth() {
        return shwrm_tffic_lst_mth;
    }

    public void setShwrm_tffic_lst_mth(Integer shwrm_tffic_lst_mth) {
        this.shwrm_tffic_lst_mth = shwrm_tffic_lst_mth;
    }

    public Integer getShwrm_tffic_6_mth() {
        return shwrm_tffic_6_mth;
    }

    public void setShwrm_tffic_6_mth(Integer shwrm_tffic_6_mth) {
        this.shwrm_tffic_6_mth = shwrm_tffic_6_mth;
    }

    public Integer getShwrm_tffic_mtht() {
        return shwrm_tffic_mtht;
    }

    public void setShwrm_tffic_mtht(Integer shwrm_tffic_mtht) {
        this.shwrm_tffic_mtht = shwrm_tffic_mtht;
    }

    public Integer getShwrm_clsng_lst_mth() {
        return shwrm_clsng_lst_mth;
    }

    public void setShwrm_clsng_lst_mth(Integer shwrm_clsng_lst_mth) {
        this.shwrm_clsng_lst_mth = shwrm_clsng_lst_mth;
    }

    public Integer getShwrm_clsng_6_mth() {
        return shwrm_clsng_6_mth;
    }

    public void setShwrm_clsng_6_mth(Integer shwrm_clsng_6_mth) {
        this.shwrm_clsng_6_mth = shwrm_clsng_6_mth;
    }

    public Integer getShwrm_clsng_mtht() {
        return shwrm_clsng_mtht;
    }

    public void setShwrm_clsng_mtht(Integer shwrm_clsng_mtht) {
        this.shwrm_clsng_mtht = shwrm_clsng_mtht;
    }

    public Date getAddedDate() {
        return addedDate;
    }

    public void setAddedDate(Date addedDate) {
        this.addedDate = addedDate;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Id
    @Column(name = "username")
    private String username;

}