Synchronicity Problems

Two users could get the same number.

count++;  //Thread 1
count++; //Thread 2
out.println; //Thread 1
out.println; //Thread 2

Synchronize method:

public synchronized void doGet(HttpServletRequest req,
                               HttpServletResponse res)

Synchronize code:

PrintWriter out = res.getWriter();
synchronized(this) {
  count++;
  out.printl(...);
}

Synchronize only needed functionality:

PrintWriter out = res.getWriter();
int local_count;
synchronized(this) {
  local_count = ++ count;}
out.println(..);