isAsyncStarted() : Checks whether request put into asynchronous mode

public boolean isAsyncStarted()

Checks if this request has been put into asynchronous mode. Return true if this request has been put into asynchronous mode, false otherwise.

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.AsyncContext;

@WebServlet(urlPatterns = {"/ProcessRequest"}, asyncSupported=true)
public class ProcessRequest extends HttpServlet {
    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse res)throws IOException, ServletException{
            System.out.println("Is Asynchronous mode of the request started " + req.isAsyncStarted());
            req.startAsync();
            System.out.println("Is Asynchronous mode of the request started " + req.isAsyncStarted());
            final AsyncContext acontext = req.getAsyncContext();
            String threadName = Thread.currentThread().getName();
            long startTime = System.currentTimeMillis();
            System.out.println("Thread " + threadName + " started at " + startTime);
            acontext.start(new Runnable() {

                public void run() {
                    String time = req.getParameter("time");
                    int wait = Integer.parseInt(time);
                    
                    try{
                        Thread.sleep(wait);
                    }
                    catch(InterruptedException e){
                        
                    }
                    HttpServletResponse response = (HttpServletResponse)acontext.getResponse();
                    try(PrintWriter out = response.getWriter()) {
                        out.println("I am done");
                    }
                    catch(Exception e){
                        
                    }
                    acontext.complete();
                }
            });
            
            long endTime = System.currentTimeMillis();
            System.out.println("Thread " + threadName + " finished at " + endTime);
            System.out.println("Total time taken is " +(endTime-startTime) + " Milli Seconds");
            System.out.println("Is Asynchronous mode of the request started " + req.isAsyncStarted());       
    }
}

Run the above servlet like below.

http://localhost:8080/servlet/ProcessRequest?time=10000

As you see the console logs, you can observe the below information messages immediately.

Info: Is Asynchronous mode of the request started false

Info: Is Asynchronous mode of the request started true

Info: Thread http-listener-1(2) started at 1405520809734

Info: Thread http-listener-1(2) finished at 1405520809737

Info: Total time taken is 3 Milli Seconds

Info: Is Asynchronous mode of the request started true

After 10 seconds you can see the response in your browser.

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