An interface is a promise: I can do these things — without saying how you grew up in the class hierarchy. Kotlin lets interfaces carry both abstract members and default implementations with bodies, so you get flexibility without the weight of multiple abstract classes.
Define the contract
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.