Ahmed,

As far as I know RS and sample-pair steganalyses are not edge-based steganalysis techniques.

Many researchers have implemented the RS algorithm, below is one of them written in Java as you preferred.

The main page is: http://vsl.sourceforge.net/

The RS program is written by Michał Węgrzyn.

http://sourceforge.net/p/vsl/code/ci/master/tree/vsl-module-steganalysis-lsb/src/main/java/pl/edu/zut/wi/vsl/modules/steganalysis/lsb/RSAnalysisImpl.java

Thank you Abbas, 

Please, Is there any explanation to understand this method well, other than original article? 

Thank you again 

Ahmed,

Apart from the original article of J. Fridrich, the best option before you is to go through the code and execute it block by block to trace what it is doing. Another code for RS which could be easier to interpret is the following Matlab code:

https://github.com/matthewgao/RS-analysis