Thanks for your reply. But I think that not really solves my problem.
I think further information will help:
I have a set of projects (~20) with individual preferences. The java
source files of all of these projects are located in a particular
folder in the file system, i.e. "C:\myFiles\". The subfolders are as
follows: "C:\myFiles\project1files", "C:\myFiles\project2files" and so
on...
Now I want to transfer all these files to another computer, so I copy
the eclipse workspace containing the project configuration and all of
the source files. But now the source files shall be located in i.e. "C:
\anotherDirectoy\".
That's why I thought a variable VAR_DIR would be advantageous, which
can be set to the base directory.

Any hints?

Thank you very much.
Andreas