How to make a custom private plugin in phonegap

How to make a custom private plugin in phonegap

Is there any way to achieve this? Everywhere I see contributing to plugin
development or making use of an existing plugin (which are public). I
would like to make a private plugin. Is this possible? I'm aware that
through eclipse (for android) I can do this. But anyway to do this using
phonegap build process so that I can make use of other advantages of using
phonegap build?