Hi,
I don't have answers to all your questions, but I can answer a few:
1. web.xml is a deployment descriptor in a web application. It contains the configurations required for the application.
2. To create a continuously running thread: I guess you are speaking of a daemon thread. These thread run in the background. To set a thread as daemon, you just have to set that property for the thread. Call threadObj.setDaemon(true).
3. From what I understand from your last question:
Runtime exception is an exception that occurs only when the application is run. For Eg: NullPointerException
Error: I guess Compile time errors would fit this category
Exception: Some java methods throw an Exception. These are some exceptions that may arise when the program is running. Eg: IOException
I hope this helps.
Regards,
Sahil.
--Smile, it makes others wonder what you are thinking.