Hi:
  We are looking at converting one of our existing java applications to a j2ee one.I wanted to hear experiences from the community on this one.

   Any experiences, pointers, recommendations,links on this topic would be greatly appreciated.

tia

splash

It would be helpful to hear why you would want to do such a thing. Some good reasons may be performance and ease of installation/distribution (in case you are going for a web GUI).

Performance is indeed one of the major reasons as is scalability, we are expecting mutifold increase in number of users due to change in buisness scenario.

  Geting back to my original question, any guidelines (Dos and Donts) to share
from someone who has done a java to j2ee conversion

tia

sp

You might need to be careful not to go too far towards 'ultimate' performance and scalability. Often, you will not need the huge array of features that J2EE and an application server provide.
Are you thinking of using EJBs? If so - be careful, as there is a learning curve there, plus development, testing and deployment processes are more complex(these can make things difficult late in project lifecycle).
You might consider looking at lightweight containers, such as the Spring Framework. Its quite easy to use, plus can function outside of an application server, making testing much much easier, yet still offering an excellent strucuture within which you can build your application.
Perhaps if you used Spring, the transition could be easier than moving towards the more heavyweight EJB-approach.