confused with server instances

Question

I have the following piece of code its working fine,no issues but i am confused,how to make more than one instances of this.Every time i run this i get "there are 1 instances running"

public class HolisticCounter extends HttpServlet {


    private static final long serialVersionUID = 1L;
static int classCount = 0;  // shared by all instances
  int count = 0;              // separate for each servlet
  static Hashtable instances = new Hashtable();  // also shared

  public void doGet(HttpServletRequest req, HttpServletResponse res) 
                               throws ServletException, IOException {
    res.setContentType("text/plain");
    PrintWriter out = res.getWriter();

    count++;
    out.println("Since loading, this servlet instance has been accessed " +
                count + " times.");

    // Keep track of the instance count by putting a reference to this
    // instance in a Hashtable. Duplicate entries are ignored. 
    // The size() method returns the number of unique instances stored.
    instances.put(this, this);
    out.println("There are currently " + 
                instances.size() + " instances.");

    classCount++;
    out.println("Across all instances, this servlet class has been " +
                "accessed " + classCount + " times.");
  }
}

It is fine. Why would you have more than one instance of a servlet? Concurrent requests will run same servlet in concurrent threads. — Piotr Gwiazda, Jan 13 '12 at 11:16
Actually the tutorial where i read it from,showed the output that "there are 2 instances running" so i was curious how to get 2 instances running — Rookie, Jan 13 '12 at 11:20
Related: http://stackoverflow.com/questions/3106452/how-do-servlets-work-instantiation-session-variables-and-multithreading/3106909#3106909 — BalusC, Jan 13 '12 at 19:06

score 4 · Accepted Answer · answered Jan 13 '12 at 11:10

4

In the vast majority of cases, there is only ever one servlet instance per <servlet> entry. The container does not need to instantiate any more, and so it reuses the same instance for every request.

The server is permitted to instantiate several, but there's usually no reason for it to do so.

answered Jan 13 '12 at 11:10

skaffman

398,947
96
818
769

thanks for the answer but can u tell me how to create another instance? – Rookie Jan 13 '12 at 11:18
@raghav: Why would you want to? – skaffman Jan 13 '12 at 11:45
Actually the tutorial where i read it from,showed the output that "there are 2 instances running" so i was curious how to get 2 instances running . – Rookie Jan 13 '12 at 12:26
@raghav: I suggest ignoring that tutorial; it's either out of date or just plain wrong. – skaffman Jan 13 '12 at 13:12

confused with server instances

1 Answers1