Hello Kishore Commons is very useful for any kind of Java development. A Struts app is just one of the possibilities. Commons has dozens of useful components that each do a definite task very well. Most of the Jakarta projects use Commons components. Check the lib directory of Tomcat, Struts... So it is quite likley that you are already using a component, framework, server... that uses Commons. Do a commons*.jar search on your machine and you might be surprised by the results.