Sams Teach Yourself Java™ in 24 Hours (Covering Java 7 and Android)

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HOUR 12:Making the Most of Existing Objects

At the top is the Objectclass.JApplethas five superclasses above it in the

hierarchy: Applet,Panel,Container,Component, and Object.

TheJAppletclass inherits attributes and behavior from each of these class-

es because each is directly above it in the hierarchy of superclasses. JApplet

does not inherit anything from the five green classes in Figure 12.1, which

includeDialogandFrame, because they are not above it in the hierarchy.

If this seems confusing, think of the hierarchy as a family tree. JApplet

inherits from its parent, the parent’s parent, and on upward. It even might

inherit some things from its great-great-great-grandparent, Object. The

JAppletclass doesn’t inherit from its siblings or its cousins, however.

Creating a new class boils down to the following task: You only have to

define the ways in which it is different from an existing class. The rest of

the work is done for you.

Inheriting Behavior and Attributes

The behavior and attributes of a class are a combination of two things: its

own behavior and attributes and all the behavior and attributes it inherits

from its superclasses.

The following are some of the behavior and attributes of JApplet:

. Theequals()method determines whether a JAppletobject has the
same value as another object.

WINDOW

DIALOG

FILEDIALOG

CONTAINER

COMPONENT

OBJECT

PANEL

APPLET

JAPPLET

SCROLLPANE

FRAME

The family tree of the JApplet
class.