Reports code which use or override package-private members which are declared in the same package in a different module. If the declaring classes are loaded by different loaders a code which access a package-private member will fail with IllegalAccessError at runtime. If a method overrides a package-private method from a class loaded by a different loader, it won't be invoked when the super method is called on an instance of the implementing class. If a method implements an abstract package-private method from a class loaded by a different loader, calling the super method on an instance of the implementing class will fail with AbstractMethodError