Game Login Server?

[TechNick6425]

I would like to create a login server, and I want to write it in Java. However, I want to store all of the users in one file, but not using SQL. What could I use to store the names?

EDIT: I would also like to know to connect and modify it with Java

[programmerjake]

XML?

[TechNick6425]

How would I manage to interface this with Java?

[quew8]

http://docs.oracle.com/javase/tutorial/jaxp/index.html or I believe there are a huge number of external libraries.