hello folks, I was trying to understand `internal`...

# android

[Suraj]

hello folks, I was trying to understand internal modifier and found that visibility is restricted to a module. And definition of module in context of gradle as per doc is :
a Gradle source set (with the exception that the test source set can access the internal declarations of main);
a)What does gradle source set mean? Does it mean a gradle module or some subset of it?
b)Do we have any advantages of using internal in a multi module project? like reduces incremental build time or so?