Custom tag library

- [Instructor] Okay, so now that we have seen…JSP standard actions, expression language,…JSTL, let's say that you want to implement a requirement…which is not allowing you to choose any tag from JST.…Let's say that's something that you want to implement…for which there is no tag existing…under the Java server pages tag library.…So, in that case, you can make your own tag library…which is the custom tag library defined…by the developer, right.…So, custom tag library is basically going…to consist of a user-defined JSP element…and, when it's a library,…of course it can contain one…or more tags bundled together…and you can bundle them in a jar file…and make sure that the jar file is used…by a few other projects…so that it promotes re-useability as well.…

Now, in order to develop a custom tag library,…you of course need to write your own tags…but as we saw, that when we write a tag on a JSP,…it's not just a tag.…There's some Java code that executes behind the tag, right?…So whenever, the JSP executes and runs,…the tag makes sure that there's some Java…