title: Writing inside Mac application package/folder with Java
body: <p>Okay, I have thought  before asking this question because at first it does sound like the age old question that boils down to "is it possible to write inside of an archive". I am new to Mac OS X but I have read that applications are just a folder with the <code>.app</code> extension and a specific file structure. So, I would like to know if it is possible to write inside of this folder, and if so how.</p>
  
  <p>The reason I ask is because in my Java program, on windows, it reads some files that are in the programs directory (the principle of Program Files) but on OSX applications don't seem to create any files (that are apparent) - so I guessed that they must store them in the <code>.app</code> folder! If I assumed wrong though, I'd like to know where applications normally store the files that they create please.</p>
  
  <p>Thanks in advance</p>
  
  <p><strong>EDIT</strong> The whole reason I ask this question is because I fear negative feedback if my application leaves files behind, so really I need informative opinions. In short, my application needs a configuration file, but it also allows users to create their own 'databases'. I now think that I will store these in the user's document folder, but I'm not sure as to whether I should delete these files when the app is deleted or just leave them. Obviously, deleting them would require me to make a package - which would just be an extra step for the user, so what do you think?... Oh yes, and the applications generates a license file upon the user entering a valid serial key - on Windows the information is stored in the registry, but on Mac I am not sure where to put the file containing this information! Any help would be much appreciated.</p>