That’s not true ... the state of the class, it’s usually better to use an interface. The design pattern template method is good example of using abstract classes. The template method pattern ...

When designing applications, it is important to know when to use an abstract class ... interfaces to create unit tests that do not depend on implementations defined in concrete classes. Design ...

The release of Java SE 15 in Sept 2020 will introduce "sealed classes ... a public abstract class that is not meant to be extended. Library authors would prefer to use interfaces to expose ...

It's a powerful but potentially messy design ... with sealed classes is that they are declared using the sealed keyword, followed by the permits clause to explicitly name the classes that can extend ...

Extension methods provide a great way for extending a class functionality -- but it's interfaces that let you use those methods anywhere you want ... me to say that extension methods are attached to ...