I downloaded jforex-sdk.zip from
https://www.dukascopy.com/client/jforexlib/I don't know if this is the easiest way because I don't know much about maven repositories.
Unzip and then run mvn clean install (on linux) where the extracted files are. Maven installation will create a folder with all the jar files. I watched the messages from the installation to see where that folder is. I took those jar files and copied them in the folder where my .java file was and compiled the file with javac -cp .:./* myfile.java on linux
if you are on windows the command should be javac -cp ./*; myfile.java. I don't know the exact way to use maven on windows, but a little time spend on google should make it clear for you as that's how i figured out how to do it on linux.