Problem running app outside it's directory

Question

Hi
I wrote an application that uses System.getProperty("user.dir") to get the path to it's directory. I need it to read certain files on app startup, and also save configuration (everything in the program directory).
Now as it turns out I cannot start the application outside it's directory. Under Windows links work ok so it's not a problem, but on linux running the app thru a symbolic/hard link when I am not in the application directory is not possible.
Also under windows I wanted to associate my app with a certain file type. Everything works ok when I run it from inside the application directory and give a full path to the file I want to open (myapp F:\somedir\file), but when I go to the file directory (F:\somedir\ - which is not where I have my application) and try to open it with my app - my app just crashes, sort of like on Linux when using links. It also creates certain files there (in F:\somedir\ for this example) that should be created in the program directory.
Is there anyway I can get around this (and not make my application less cross-platform)?
Thanks in advance
mike

Answer 1

I think a better way to do it is to not use "user.dir"; you've already correctly concluded that you don't want hard paths to directories.
A better solution is to use the class loader and its getResourceAsStream method to get an InputStream for those files you want to read.
For writing, create a /tmp directory or have a path that you can configure externally.
What is it you're saving? "everything in the program directory" isn't very descriptive. Do you really need a relational database instead?
As far as file types go, use a FilenameFilter to choose a particular type.
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