Java cannot reference non final variables

Continue to give me the following code:

package com.gwt.churchweb.churchweblogin.client;

import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.FlexTable;
import com.google.gwt.user.client.ui.Text@R_79_2419@;
import com.google.gwt.user.client.ui.HasHorizontalAlignment;
import com.google.gwt.user.client.ui.Check@R_79_2419@;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.user.client.Window;

public class Login extends Composite {

    public Login() {

        VerticalPanel verticalPanel = new VerticalPanel();
        initWidget(verticalPanel);
        verticalPanel.setSize("329px","186px");

        Label lblNewLabel = new Label("Sign into your account");
        lblNewLabel.setStyleName("gwt-Login-SigninLabel");
        verticalPanel.add(lblNewLabel);

        FlexTable flexTable = new FlexTable();
        verticalPanel.add(flexTable);
        flexTable.setWidth("308px");

        Label lblNewLabel_1 = new Label("Username:");
        lblNewLabel_1.setStyleName("gwt-Label-Login");
        flexTable.setWidget(0,lblNewLabel_1);
        lblNewLabel_1.setWidth("72px");

        Text@R_79_2419@ text@R_79_2419@Username = new Text@R_79_2419@();
        text@R_79_2419@Username.setStyleName("gwt-LoginText@R_79_2419@");
        flexTable.setWidget(0,1,text@R_79_2419@Username);
        text@R_79_2419@Username.setWidth("204px");

        Label lblNewLabel_2 = new Label("Password:");
        lblNewLabel_2.setStyleName("gwt-Label-Login");
        flexTable.setWidget(1,lblNewLabel_2);
        lblNewLabel_2.setWidth("66px");

        Text@R_79_2419@ text@R_79_2419@Password = new Text@R_79_2419@();
        text@R_79_2419@Password.setStyleName("gwt-LoginText@R_79_2419@");
        flexTable.setWidget(1,text@R_79_2419@Password);
        text@R_79_2419@Password.setWidth("204px");
        flexTable.getCellFormatter().setHorizontalAlignment(0,HasHorizontalAlignment.ALIGN_LEFT);
        flexTable.getCellFormatter().setHorizontalAlignment(1,HasHorizontalAlignment.ALIGN_LEFT);

        Check@R_79_2419@ chckbxRememberMeOn = new Check@R_79_2419@("Remember me on this computer");
        chckbxRememberMeOn.setStyleName("gwt-Check@R_79_2419@-Login");
        flexTable.setWidget(2,chckbxRememberMeOn);

        Button btnSignIn = new Button("Sign In");
        btnSignIn.addClickHandler(new ClickHandler() {
            public void onClick(ClickEvent event) {
                if (text@R_79_2419@Username.getText().length() == 0
                        || text@R_79_2419@Password.getText().length() == 0) {
                        Window.alert("Username or password is empty."); 
                    }
            }
        });

        btnSignIn.setStyleName("gwt-Login-SigninButton");
        flexTable.setWidget(3,btnSignIn);



    }


}

Solution

final Text@R_79_2419@ text@R_79_2419@Username = new Text@R_79_2419@();

final Text@R_79_2419@ text@R_79_2419@Username = new Text@R_79_2419@();

and

final Text@R_79_2419@ text@R_79_2419@Password = new Text@R_79_2419@();

It should be solved

Java requires that variables in internal classes be referenced as final variables (for concurrency management reasons, I think)