Originally posted by Rauhl Roy: ... In other words, without writing the main method we are able to run the servlet program. why is it possible throgh servlets ?
There is a main method but it's not in the servlets themselves. It's in the code for the container. Once started, it runs continuously, waiting for HTTP requests. When it receives one, as Gregg said, it instanciates a servlet to handle it.
One part of the specification is implemented by vendor and using the other part of the specification you are suppose to write the pluggable component (servlets) that would fit into the first specifications implementation (that is the container).So there is a main method ,but that lies with the container code and at later part of the flow your code gets enxcuted.