quite some things were said about the how or why, mostly on technical terms or money. Taking the viewpoint of a salesperson (yuck!) I think three steps are required:

1. Convince your customer that your technology (and people) can do the job. Easily. Have done it before. Many times. ;-)

   For each of your points:

   • Accept credit cards.
     No prob, someone above pointed out perl examples.
   • Manage user accounts.
     No prob, we can interface with the OS user management or implement our own.
   • Serve information from databases.
     DBI rulez (at least I never had probs getting what I wanted from a database via DBI; let's you switch databases if you want, just as JDBC). If I remember correctly, btrott has deeper knowledge of DBI, check his home node.
   • Handle several XML interfaces to external systems.
     Currently I am using XML::Parser and XML::XSLT with _great_ success. Main problem may become memory usage, but that is inherent in the DOM specification, anyway, so no different in Java.
2. Point out at least one critical weakness in the other approach. One might ask: how do I handle many concurrent sessions without the need for a very big (read: expensive) machine like IBM SP or Sun E?k ?
3. Make your offer (how much, how long).

Andreas