why DD is in XML?

why deployment descriptor in xml file?

Why not?

need clarity....why xml only?why not others

Such as? You'll need to put a little more effort into your question.

thanks

For example: what other formats would you expect, and why?

The answer is the same as the answer to all the other "why is it like that" questions I see around here: it's that way because the designers decided to do it that way.

Now perhaps you meant to ask why the designers decided to use XML. Or perhaps you meant to ask why XML might be a better choice than some other format. But those are very different questions and we shouldn't be made to guess what you meant by your question. So... if you have a specific question, please ask it.

you are right paul....thanks

Years ago when servlets first appeared I worked with a pioneering commercial version.

It used properties files to define parameters to the container - what a confusing mess.

Because of the limited ability of the property file concept of name/value pairs to communicate structure, we ended up with multiple files having confusing names containing properties with confusing names. Switching to web.xml was a big improvement.

Bill

Comparing XML to *.properties files:

In my very first J2EE project, back in 2001, we used BEA WebLogic version 5.1. You had to configure it in one giant *.properties file. That was a big mess. In WebLogic 6.0, the configuration was done in XML, which was much more clear.

A *.properties file is just a flat list of key-value pairs. XML has hierarchical tree structure, so that you can organise things in a much better way.