如何在andorid / eclipse中为pro和lite创建2个具有相同名称的jar

I have a pro version and a free version. What I plan to do is to put my code in a jar (lib) and have a flag reg=1 in code itself. And I will build 2 jars one with reg=0 for free and other with reg=1 for pro.I have a pro version and a free version. What I