Final Review Sheet

Inheritance and Polymorphism

• Derived class (or subclass) inherits all of the features (data and methods) of the base class (or superclass)
• Know how to derive a class from another, with keyword extends

     class DerivedClass extends BaseClass
    

• The use of super to invoke parent constructors and methods
• Understand overriding methods in derived classes
• Understand the uses of final, when applied to a class and/or to a method
• Every class is derived in some way from class Object. Understand these 3 special methods inherited from Object by every class:
  • equals()
  • toString()
  • clone()
• Understand the modifier protected, and what it means when applied to class data and methods
• Abstract classes and their relationship with abstract methods
• Understand polymorphism and dynamic binding
  • How base class variables can be attached to derived class objects
  • If class D is derived from base class B, as object of type D can be assigned to a B variable. Similarly, the D object can be passed into a method where a parameter of type B is expected
  • Base class methods can be overridden in derived classes
  • Fynamic binding allows method calls (through base class variables) to still invoke child versions of overridden methods
  • Know when casting is necessary between parent and child, and when it is not
  • Understand the instanceof operator, and when it is useful in casting between related reference types
• Know how a class declares that it will implement an interface (i.e. keyword implements)

     class ClassName implements InterfaceName
    

• Understand what it means when a class implements an interface. Specifically, the class must implement the methods listed in the interface
• Understand relationship of data and methods with interfaces (i.e. what kind of data and methods go in an interface?)
• Understand the basic interfaces discussed in examples (Comparable and Clonable)
• Understand the usage of interface types and base class types, and how they relate to the derived types:
  • If class A implements interface I, an object of type A can be assigned to an I variable. Similarly, the A object can be passed into a method where a parameter of type I is expected
• Know the rules on extending classes, extending interfaces, and implementing interfaces
  • A class can directly extend only one class
  • A class can implement many interfaces
  • An interface can extend many interfaces

GUI Intro -- concepts and basic libraries

Basic Concepts

• java.awt -- original Java GUI package
• javax.swing -- newer GUI package containing the library of "Swing components"
• Know what a component is
• Know what a container is
• Know the three "top-level" containers!
• Know what an event is, and how it relates to GUI applications

Painting with class Graphics

• Understand when the paintComponent() method gets called for a component. Especially the "system-level triggers" that were discussed
• Understand what kinds of drawing can be done inside paintComponent() through the Graphics class methods
• These include draw methods for shapes like: lines, ovals, rectangles, polygons, round rectangles, arcs, and strings
• Understand the calls we've seen in examples that used class Graphics, including the draw and fill methods, as well as the methods for changing colors and fonts
• Understand the basic use of the Color class, to create a color using the RGB color scheme, or one of the Color constants
• Understand the basic use of the Font class, to create a font
• Recall that to create a font, you must specify:
  • Font name (physical name or logical (family) name)
  • Font style (plain, bold, italics, or both bold and italics)
  • Point size
• Know how to set up a polygon (it requires sets of x,y coordinates, and it can be set up with two parallel arrays, one for x coordinates and one for y coordinates), and how to draw it with class Graphics
• Understand the difference between the Graphics and Graphics2D classes
• Understand the Graphics2D methods draw() and fill(), as well as what types of things constitute Shapes that can be passed in
• Understand the basic shape types in the Java2D framework, including GeneralPath
• Understand all of the drawing examples we've looked at so far in class (Ch. 12)