A functional interface has exactly one abstract method. It can be implemented by a lambda expression or a method reference — a compact pointer to an existing method. Method references make code cleaner when the lambda just calls an existing method.
@FunctionalInterface
Content is available with subscription.
Get full access to all courses on the platform for one year with a single payment.
▼
Unlike other platforms that charge per course, here you get everything for one price, and after one year of use there will be no automatic charge for the following year.