An inline function replaces the call to the function by the body of the function, thus reducing the overhead of saving the context in stack. This is good for functions which are small in size and called occasionally. A recursive function calls an instance of itself and thus can be a deeply nested. Different compilers handle this differently. Some will inline it up to a certain depth and then call a non-inlined instance for further recursion; others will not inline the function at all and generate a normal function call.

Recursion is when a method calls itself.