What are sealed classes in Java 17?

You can follow this link for examples.

In short sealed classes gives you the control of which models, classes etc. that can implement or extend that class/interface.

Example from the link:

public sealed interface Service permits Car, Truck {

    int getMaxServiceIntervalInMonths();

    default int getMaxDistanceBetweenServicesInKilometers() {
        return 100000;
    }
}

This interface only permits Car and Truck to implement it.