Relative path in eclipse RCP

Hello, my problem is as follows:

I have an eclipse installed in folder D:\eclipse\. My project folder is in d:\java_workspace\ProjectName\. My application will need to read files stored in local directory (e.g. d:\java_workspace\ProjectName\data\somefile.txt), but when I point to the file with relative path ".\data\somefile.txt", eclipse looks for the file here: d:\eclipse\data\somefile.txt.

Why? How to change it to look in project folder? It has to be possible as eclipse branding is by default stored in ProjectFolder\icons (or something similar), right?

EDIT:

Ok, I got it, one need to change working directory in run configuration.