Can class extend multiple abstract classes?
Basically, the rule says that you can inherit from (extend) as many classes as you want, but if you do, only one of those classes can contain concrete (implemented) methods.
A class can extend at most one abstract class, but may implement many interfaces.
That is, Java supports a limited form of multiple inheritance..
Can we inherit one abstract class to another abstract class?
Yes you can inherit an abstract class from another abstract class. When you want any class to inherit from another class, you will want to watch out (most of the time) for the sealed modifier.
Can an abstract class extend concrete?
An abstract class always extends a concrete class ( java. lang. … If you want to instantiate it, you will have to subclass it with a concrete implementation of those abstract methods and instantiate it through the concrete class.
Can abstract class be empty?
A empty abstract class can be used to group together classes. This is in order to show some intent and to ensure the single responsibility principle that a class should have just one purpose. The example you give uses an interface, not an empty abstract class.
Can an abstract class be extended?
Abstract classes are similar to interfaces. You cannot instantiate them, and they may contain a mix of methods declared with or without an implementation. … In addition, you can extend only one class, whether or not it is abstract, whereas you can implement any number of interfaces.
Can abstract class extend another abstract class in Java?
An abstract class can extend another abstract class. And any concrete subclasses must ensure that all abstract methods are implemented. Abstract classes can themselves have concrete implementations of methods. These methods are inherited just like a method in a non-abstract class.