Servlet. Race condition.

Somewhere in html:

form action="SynchTest" method="POST" name="form1"
input name="SubmitBtn" type="submit" value="SUBMIT"

_______________
public class SynchTest extends HttpServlet {
        Asynch a = new Asynch();

    protected void processRequest(HttpServletRequest request, 
                                  HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();

        try {
            String title = "SynchTest";
            int y = 40;
            if(a.getValue() > y) {
                try {
                    Thread.sleep(5000);
                } catch (InterruptedException ex) {
                    out.print(ex.toString());
                }
                a.subtract(y);
            }
            String value = "Value is: " 
                            + String.valueOf(a.getValue()); 
            
            String threadInfo = Thread.currentThread().getName();
            value = value +"\n" + "Thread name is: " + threadInfo;
            out.println(MyHTML_util.getHTML(title,value));
        } finally {            
            out.close();
        }
    }
_____________________ 

 public class Asynch {
    private int x = 100;
    public int subtract(int y){
            x = x-y;
        return x;
    }
    public int getValue(){
        return x;   
    }
}

(3 requests from different tabs) produced following result:
Value is: 60
Thread name is: http-thread-pool-8080(4)

Value is: 20
Thread name is: http-thread-pool-8080(5)

Value is: -20
Thread name is: http-thread-pool-8080(1)

After one hour the result was updated (again 60):
Value is: 60
Thread name is: http-thread-pool-8080(4)


So I know JVM creates only one instance of servlet and a separated thread for each request.