The concept of interfaces and abstract classes is not the same. Interface is an abstract of the action, an abstract class is an abstract roots.
When you look at the essence of a thing when the abstract class; when you focus on one operation when using the interface.
The first point. Interface can be multiple inheritance, abstract classes, not
the second point. Interface, after jdk1.8 static and default may be modified to implement the method and, at this time may be a subclass that implements the interface default method for modifying the interface name is modified static call the static method (default interface or only for the switch case); and the method may be implemented partially abstract class.
fourth point. Basic data type interface is static and not drawn as the class.