In Java the extends clause is used to specify inheritance.

The subclass of a non-abstract class can be declared abstract.

All the members of the superclass are inherited by the subclass.

A final class can be abstract.

A class in which all the members are declared private, cannot be declared public.

Inheritance defines a has-a relationship between a superclass and its subclasses.

Every Java object has a public method named equals.

Every Java object has a public method named length.

A class can extend any number of other classes.

A non-final class can be extended by any number of classes.