A keyword used to make one class a subclass of another, for example, class subclass extends superclass
A Java reserved word used to specify the parent class in the definition of a child class
A relationship from one use case to another, specifying how the behavior defined for the first use case can be inserted into the behavior defined for the second use case
A keyword used in a class or interface declaration In class definitions, extends specifies the superclass of the class being defined The keyword extends is followed by the name of the superclass For interfaces, the extends keyword is followed by a list of classes See: implement
Class X extends class Y to add functionality, either by adding fields or methods to class Y, or by overriding methods of class Y An interface extends another interface by adding methods Class X is said to be a subclass of class Y See also derived from
The extends keyword is used in a class declaration to specify the superclass of the class being defined The class being defined has access to all the public and protected variables and methods of the superclass (or, if the class being defined is in the same package, it has access to all non-private variables and methods) If a class definition omits the extends clause, its superclass is taken to be java lang Object