Are there any free or cheap tools that can display XML schemas as diagrams and allow visual editing?
VS.NET Express (not sure about visual editing)
Well, that does answer the question. It's not a very detailed answer, and you might not even consider it helpful, but the proper action for answers that are not helpful is downvoting, not flagging.
After all, the text for flagging as not an answer reads:
This was posted as an answer, but it does not answer the question. It should possibly be an edit, a comment, another question, or deleted altogether.
Again, it answers the question, so it is an answer.
I'm writing a simple web server. I'd like to let the user set the port the server listen to, but how could I know if the port the user input is already in use or not?(if I know it's already in use, I can tell them to input another one.)
Just another approach :p try to connect to that port on localhost. (comments and down-votes are cooooomiiiiiiing...)
That is just plain wrong (and somehow should edit the last part out), but as the moderator said:
[...] flags should not be used to indicate technical inaccuracies, or an altogether wrong answer.
Wrong answers aren't potential edits, comments or other questions. Just wrong answers.
The other answers, I don't understand. I know little to nothing about Eclipse, mySQL and Java.
But it looks like they fall in the same category as the first two: bad answers (but answers after all).