What's a better approach for enabling thread-safe servlets and JSPs

Question :What's a better approach for enabling thread-safe servlets and JSPs?
SingleThreadModel Interface or Synchronization? (JSP)
Answer :Although the SingleThreadModel technique is easy to use, and works well
for low volume sites, it does not scale well. If you anticipate your users to
increase in the future, you may be better off implementing explicit
synchronization for your shared data. The key however, is to effectively
minimize the amount of code that is synchronzied so that you take
maximum advantage of multithreading.
Also, note that SingleThreadModel is pretty resource intensive from the
server's perspective. The most serious issue however is when the number
of concurrent requests exhaust the servlet instance pool. In that case, all
the unserviced requests are queued until something becomes free - which
results in poor performance. Since the usage is non-deterministic, it may
not help much even if you did add more memory and increased the size of
the instance pool.