Introduction
Class Definition
Data Fields
Methods
Constructors
Instantiation
  Demo 1
  Demo 2
Static Members
  Demo 3
Value&Reference
  Demo 4
Overloading
   Demo 5
Wrappers 
  Demo 6
Autobox/Unbox
   Demo 7
Arrays
  Demo 8
Exceptions
Exercises

We present in this chapter the basics of Java classes and objects. In Java, the class is paramount. Essentially all coding resides within class definitions. (Note: we use the term object and instance interchangeably.)

• Class Definition - all the qualities of a class are specified in the class defintion, which consists of:
  • Data Fields
  • Methods
  • Constructors
  • (Member classes, or inner classes, will be discussed in Chapter 7)
• Instantiation - Once a class is defined you can create an instance of it
  • Object References - Java's pointers to objects
  • Access Fields and Methods
  • Demo 1
  • Demo 2
• Static (or Class) Members - Java's version of global data and functions
  • Demo 3
• Value vs. Reference - the difference in the way primitive variables and reference variables are passed as method arguments.
  • Primitive type values as method arguments.
  • Modifying reference variables
  • References as method arguments
  • Demo 4
• Overloading - methods in the same class with the same name but different argument lists are said to be overloaded.
  • Demo 5
• Wrapper classes for the primitive types
  • Demo 6
• Arrays - brief introduction to this important class
  • Demo 7
• Exceptions - Java error handling.

If this is your first encounter withobject oriented programming, you may want to read the following tutorial sections in the Chapter 3: Supplements section:

• Comparison to data types such as integers and boolean types to classes.
• Analogies for classes and objects
• Classes and objects in memory and the processor.

If you already know OOP from other languages, you may be interested in these supplementary topics:

• Java vs C++.
• Java memory management and garbage collection
• Objects and Classes in the JVM

Latest update: Oct.5, 2005

           Tech
OOP in Tech Apps
Complex Number
Histogram Class
  Demo
More Wrappers

           Physics
OOP in Physics
Particle Class
Root Finding
  Demo 1
Newton Methods
  Demo 2
Exercises