Eclipse Java launch configuration file path

I'm looking for a file where Eclipse stores its launch configurations. I'm doing some Java development in Ubuntu.

One of the executables i'm developing requires an output from another executable as a argument to it. So say, the output of 'B' needs to be passed as a commandline argument to 'A'. In the Eclipse, I don't want to manually change the "Run Configuration" every time. Where does Eclipse store these configurations esp the arguments?

I found a "eclipseArguments.txt" in the extras folder of the project but this isn't the same as the arguments I'm passing into the Run Configurations. The ".project" file doesn't contain it either. I'm confused.

Thanks for the help.