7.3 Java1638 java oop local classes

Revised: Wed May 11 15:29:28 CDT 2016

This page is included in the following Books:

• ITSE2317 - Java Programming (Intermediate)
• Object-Oriented Programming (OOP) with Java

Table of contents

• Preface
  • Viewing tip
    • Figures
    • Listings
• Preview
  • What can you include in a class definition?
  • What is a local class?
  • Why use local classes?
  • Local classes versus member classes
  • The scope of a local class
  • Restrictions on local classes
• Discussion and sample code
  • Class hierarchy
  • Overall program structure and behavior
    • The controlling class
    • The class named X
    • The class named Y
    • The class named A
    • The local class named B
• Run the program
• Summary
• What's next?
• Miscellaneous
• Complete program listing
• Figures
• Listings

Preface

This module is one in a collection of modules designed for teaching ITSE2317 - Java Programming (Intermediate) at Austin Community College in Austin, TX.

(Editor's note: As you read this module, you will see that it was originally written around 2003. However, despite many improvements in Java sincethen, most of what was true then is still true in 2013.)

This module makes several references to my website, which is located at (External Link) .

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the Figuresand Listings while you are reading about them.

Figures

• Figure 1 . Class files produced by the program.
• Figure 2 . Screen output.
• Figure 3 . Screen output.
• Figure 4 . Screen output.
• Figure 5 . Screen output.
• Figure 6 . Screen output.
• Figure 7 . Screen output.
• Figure 8 . Screen output.
• Figure 9 . Screen output.

Listings

• Listing 1 . The controlling class named InnerClasses07.
• Listing 2 . The class named X.
• Listing 3 . The class named Y.
• Listing 4 . Beginning of the class named A.
• Listing 5 . The showA method in class A.
• Listing 6 . The delay method in class A.
• Listing 7 . Beginning the meth method in class A.
• Listing 8 . Set value of blank final variable.
• Listing 9 . Beginning of class definition for local class B.
• Listing 10 . Instantiate two objects of local class B.
• Listing 11 . Call showB on the first object.
• Listing 12 . Beginning of showB method in local class B.
• Listing 13 . More code from showB method.
• Listing 14 . Use of the keyword this.
• Listing 15 . Illustrate the inheritance hierarchy.
• Listing 16 . Call showB method on second object.
• Listing 17 . Complete program listing.

Preview

What can you include in a class definition ?

There are several different kinds of items that can be included in a class definition. As you learned in the earlier modules in this series, the listincludes:

• Static variables
• Instance variables
• Static methods
• Instance methods
• Constructors
• Static initializer blocks
• Instance initializers

Can also contain other class definitions

As you learned in the previous module , a class definition can also contain the following three kinds of inner classes:

• Member classes
• Local classes
• Anonymous classes

The previous module explained member classes. This module will explain local classes. The next module will explain anonymous classes.