submitting correct username and password, it again come in login.jsp

i am submit username and password in login.jsp, after submit correct username and password, it again come in login.jsp.

Here some files:

Struts.xml:

mypackage.xml:

LoginAction.java:

package com.struts2;
import java.sql.*;
import com.opensymphony.xwork2.ActionSupport;
public class LoginAction extends ActionSupport{

private static final long serialVersionUID = 1L;
  
    public String execute() throws Exception {
    	
        if (this.username_txt.equals("school")
               && this.password_txt.equals("school")) {
  System.out.println("now going for success********************");
          return "success";
       } else {
System.out.println("here for error------------------");
            addActionError(getText("error.login"));
         return "error";
     }
   }
     private String username_txt;
    private String password_txt;
        public String getPassword_txt() {
        return password_txt;
    }
    public void setPassword_txt(String password_txt) {
        this.password_txt = password_txt;
    }
    public String getUsername_txt() {
        return username_txt;
    }
    public void setUsername_txt(String username_txt) {
        this.username_txt = username_txt;
    }  
}

login.jsp:

please suggest.