Code.org Learning

• Classes
• Class Instances
• Calling an Object
• Extending (Class Hierarchy)

Classes

Java classes are the basic building block, like a template for objects of the class. A class is defined in its own .java file, and the name of the file has to match with the class name.

Class Instances

Class instances are objects of a class. To instance a class as an object, first type the class name, then the object name, equals new class();.

Calling an Object

You can call an object to perform a specific funciton. To do so, first write the object instance name, a period, and then the method called.

Extending (Class Hierarchy)

Extends in java “extends” a class. The class created is inherited from another class, but more methods can be written in addition to the methods already in the original class. A subclass is the class that inherits, while the superclass is the class being inherited from.