Starting from EJB 2.1, Timer Services are available for building J2EE Applications that depends on time based services. Time based services are mostly used in scheduling applications. Technically, these scheduling applications are called workflows. A workflow defines a configurable sequence of activities or tasks that will take place at a particular point of time. Before EJB 2.1, one has to manually code for building and deploying time-based workflow systems. But, with the invent of EJB 3.0, thanks to Annotations and Dependency injections, life has become still more easier for creating such applications.