<form action="addAnimal" method="post">
            <fieldset>
                    <legend>What is Your Favorite Pet?</legend>
                            <input type="checkbox" name="animal" value="Cat"/>Cats <br />
                            <input type="checkbox" name="animal" value="Dog" />Dogs<br />
                            <input type="checkbox" name="animal" value="Bird" />Birds<br />
                            <input type="submit" value="Submit now" />
            </fieldset>
    </form>

package com.bean;

import com.dao.AnimalDao;
import com.opensymphony.xwork2.ActionSupport;

public class Animal extends ActionSupport {

    private String animal;

    public String getAnimal() {
        return animal;
    }

    public void setAnimal(String animal) {
        this.animal = animal;
    }

    public String execute(){
        AnimalDao.addAnimal(this);
        return SUCCESS;
    }
}

import java.util.Map;

import org.apache.struts2.dispatcher.SessionMap;
import org.apache.struts2.interceptor.SessionAware;

import com.bean.Animal;

import com.connection.DatabaseConnection;
import com.opensymphony.xwork2.ActionSupport;

public class AnimalDao extends ActionSupport implements SessionAware {

    SessionMap<String,Object> map;
        public static void addAnimal(Animal animal) {
        // TODO Auto-generated method stub
        try{
            Connection con=DatabaseConnection.Dbconnection();
            String sql="insert into chk values(?)";
            PreparedStatement ps=con.prepareStatement(sql);
            ps.setString(1,animal.getAnimal());
            ps.executeUpdate();

            }catch(Exception e){

        }

    }

    public String retriveAnimal(){
        ArrayList<Animal> aList=new ArrayList<Animal>();
        try{
            Connection con=DatabaseConnection.Dbconnection();
            String sql="select * from chk";
            PreparedStatement ps=con.prepareStatement(sql);
            ResultSet rs=ps.executeQuery();
            while(rs.next()){
                Animal a=new Animal();
                a.setAnimal(rs.getString(1));
                aList.add(a);
                map.put("aList",aList);
            }

        }catch(Exception e){
            System.out.println(e);
        }
        return SUCCESS;
    }

    @Override
    public void setSession(Map<String, Object> map) {
        // TODO Auto-generated method stub
        this.map=(SessionMap<String, Object>) map;

    }

}

<action name="addAnimal" class="com.bean.Animal">

            <result name="success">index.jsp</result>

        </action>

        <action name="chkbox" class="com.dao.AnimalDao" method="retriveAnimal">

            <result name="success">viewuser.jsp</result>

        </action>

<s:iterator value="#session.aList" var="stat">
                            <s:checkbox name="animal[%{#stat.index}]" value=""/>
                        </s:iterator>