What is SingleThreadModel interface?
SingleThreadModel interface was provided for thread safety and it guarantees that no two threads will execute concurrently in the servlet’s service method. However, SingleThreadModel does not solve all thread-safety issues. For example, session attributes and static variables can still be accessed by multiple requests on multiple threads at the same time, even when SingleThreadModel servlets are used. Also, it takes out all the benefits of multithreading support of servlets, that’s why this interface is Deprecated in Servlet 2.4.
