Where is play! framework store @singleton object

Please tell me where is Play! Framework store @Singleton object. When update page on browser, count values increased. Small example below.

package controllers;

import javax.inject.*;
import play.*;
import play.mvc.*;

@Singleton
public class CountController extends Controller {

    private int counter = 1;

    public Result count() {
        retu ok(Integer.toString(counter++));
    }
}