I do not know specifically about Tomcat. But I feel, where there is a change that results in re-loading a class, the server may need a re-start. But a chnage of something like changing the default JSP would not need a re-start.
Tina
Alongwith being a good coder, try to be a good professional as well!
Hi "NO NEED TO RESTART THE SERVER" Every web application must have web.xml. Basically whenever there is a change in web.xml you need to restart the that particular web application. If there is facility to restart the single web application then you can simply restart that web application BUT NO NEED TO RESTART THE SERVER.
Server needs to restart only in case of changes which are shared by all web applications such as modification/addition/deletion of common libraries (xyz.jar)