Is your feature request related to a problem? Please describe.
The rule LooseCoupling flags implemented classes when interfaces suffice. It prescribes coding against an interface as against implementor classes.
It currently checks for Collections API classes. Please extend the rule so that developers can specify user-defined classes as well.

Describe the solution you'd like
The rule must be made configurable so that users can define interfaces and implementor classes from their application's source base.

Describe alternatives you've considered
None that I know of.

Additional context

None.

Other issues for the same rule:

• [java] LooseCoupling must ignore class literals: ArrayList.class #2464
• [java] LooseCoupling false-positive with methods only available on concrete collection class #1218