load on startup tag reference - novalexei/mod_servlet GitHub Wiki
#####<load-on-startup>
This tag specifies that the servlet should be loaded automatically when the web application is started.
The value is a single positive integer, which specifies the loading order. Servlets with lower values are loaded before servlets with higher values (ie: a servlet with a load-on-startup value of 1 or 5 is loaded before a servlet with a value of 10 or 20).
If no value is provided in this tag, than the container will load this servlet in the order of its <servlet> tag in web.xml file, but after loading all the servlets with valid value in load-on-startup tag.
When loaded, the init() method of the servlet is called. Therefore this tag provides a good way to do the following:
- start any daemon threads, such as a server listening on a TCP/IP port, or a background maintenance thread
- perform initialisation of the application
If no load-on-startup value is specified, the servlet will be loaded when the container decides it needs to be loaded - typically on it's first access. This is suitable for servlets that don't need to perform special initialisation.