Fix error message from javac
Fix error message from javac

With java solutions, if there aren't any .java files in the #{Euler.root} directory
javac would error out and throw a help message, now it won't be run unless a .java file or more exist

yaworsw/euler-manager,yaworsw/euler-manager,yaworsw/euler-manager,yaworsw/euler-manager,yaworsw/euler-manager,yaworsw/euler-manager,yaworsw/euler-manager