Why POJO web services does not require Binding?

Hi Folks,

Recently one of my friends put forth this question to me ?
Why POJO web services does not require binding and what are the limitations of POJO web services?

I tried convincing him by giving many answers like, When you are dealing with Business web services you need some kind of contract , so you need to bind the Java objects with the XML data together and also to handle security of the data passing between systems, He didnt agree to any of my suggestions?

Then I asked him can you tell me when do you use a Java Bean vs Java class,to see whether he gets the point here,but no luck, he is a hard nut to crack.

So my question to everyone of folks interested in POJO Web Services,please provide me any answers to this question and avoid more embarrassment for me.

Cheers,
Yaseen