I am really very new to Java. I am working on non-network application where there are mulitiple users, each with passwords. It is a financial management system with each user having many financial goals, expenditures, and accounts, and each account has many transactions. I first thought that using XML as a information retrieval and saving system would be the best way to goal. I then added the JDOM jars to be able to create and read the XML. This is causing nothing but headache and leading to no success. I am getting errors where I should not be (I have other posts regarding these) as my code is exactly like that of the tutorials. Then when it does work, it does not save the whole xml tree, just what i just added deleting the rest. So, as a general question, what IO system would be best for a program like this? (as said, non-network 1 computer application)?
When you say "an IO system", am I correct in assuming you want to design a structure or framework in which to store your data?
There are various factors to look at, such as the quantity of data to be stored, the frequency and granularity of changes, whether it will be accessed and updated by multiple users simultaneously, and so on.
Whether it's easy to do the programming for your choice of data structure should not be a primary factor in making the choice.
Based on your brief description, a database would have been higher on my short list of structures than an XML document, but then you only provided a brief description so as an analyst, I would be asking more questions before making a decision. At any rate, this isn't a question about XML so I'm going to find a better home for the question.