DEFINATION OF SOME JAVA CLASSES

If this is your first encounter with object-oriented programming, a lot of the information in this lesson is going to seem really theoretical and overwhelming. Fear not-the further along in this book you get, and the more Java classes and applications you create, the easier it is to understand.
One of the biggest hurdles of object-oriented programming is not necessarily the concepts; it's their names. OOP has lots of jargon surrounding it. To summarize today's material, here's a glossary of terms and concepts you learned today:

class:

 A template for an object, which contains variables and methods representing behavior and attributes. Classes can inherit variables and methods from other classes.

class method:

A method defined in a class, which operates on the class itself and can be called via the class or any of its instances.
class variable:A variable that is "owned" by the class and all its instances as a whole and is stored in the class.

instance:
 The same thing as an object; each object is an instance of some class.
instance method:
A method defined in a class, which operates on an instance of that class. Instance methods are usually called just methods.
instance variable:
A variable that is owned by an individual instance and whose value is stored in the instance.
interface:
A collection of abstract behavior specifications that individual classes can then implement.
object:
A concrete instance of some class. Multiple objects that are instances of the same class have access to the same methods, but often have different values for their instance variables.
package:
A collection of classes and interfaces. Classes from packages other than java.lang must be explicitly imported or referred to by full package name.
subclass:
A class lower in the inheritance hierarchy than its parent, the superclass. When you create a new class, it's often called subclassing.
superclass:
A class further up in the inheritance hierarchy than its child, the subclass.

Java's Future And why Learn Java??

What's in store for Java in the future? A number of new developments have been brewing (pardon the pun):

• Sun is developing a number of new features for the Java environment, including a number of new class libraries for database integration, multimedia, electronic commerce, and other uses. Sun also has a Java-based Web server, a Java-based hardware chip (with which you can write Java-specific systems), and a Java-based operating system. You'll learn about all these things later in this book. The 1.1 release of the JDK will include many of these features; others will be released as separate packages.
• Sun is also developing a framework called Java Beans, which will allow the development of component objects in Java, similarly to Microsoft's ActiveX (OLE) tech-nology. These different components can then be easily combined and interact with each other using standard component assembly tools. You'll learn more about Java Beans later in this book.
• Java capabilities will be incorporated into a wide variety of operating systems, including Solaris, Windows 95, and MacOS. This means that Java applications (as opposed to applets) can run nearly anywhere without needing additional software to be installed.
• Many companies are working on performance enhancements for Java programs, including the aforementioned Java chip and what are called just-in-time compilers.

Why Learn Java?

At the moment, probably the most compelling reason to learn Java-and probably the reason you bought this book-is that applets are written in Java. Even if that were not the case, Java as a programming language has significant advantages over other languages and other environments that make it suitable for just about any programming task. This section describes some of those advantages.

Java Is Platform Independent

Platform independence-that is, the ability of a program to move easily from one computer system to another-is one of the most significant advantages that Java has over other programming languages, particularly if your software needs to run on many different platforms. If you're writing software for the World Wide Web, being able to run the same program on many different systems is crucial to that program's success. Java is platform independent at both the source and the binary level.

Java Is Object Oriented

To some, the object-oriented programming (OOP) technique is merely a way of organizing programs, and it can be accomplished using any language. Working with a real object-oriented language and programming environment, however, enables you to take full advantage of object-oriented methodology and its capabilities for creating flexible, modular programs and reusing code.

Java Is Easy to Learn

In addition to its portability and object orientation, one of Java's initial design goals was to be small and simple, and therefore easier to write, easier to compile, easier to debug, and, best of all, easy to learn. Keeping the language small also makes it more robust because there are fewer chances for programmers to make mistakes that are difficult to fix. Despite its size and simple design, however, Java still has a great deal of power and flexibility.

WHAT IS JAVA ????

Based on the enormous amount of press Java is getting and the amount

of excitement it has generated, you may get the impression that Java will 

save the world-or at least solve all the problems of the Internet. Not so. 

Java's hype has run far ahead of its capabilities, and while Java is indeed 

new and interesting, it really is another programming language with which 

you write programs that run on the Internet. In this respect, Java is closer 

to popular programming languages such as C, C++, Visual Basic, or Pascal,

than it is to a page description language such as HTML, 

or a very simple scripting language such as JavaScript.

More specifically, Java is an object-oriented programming language developed 

by Sun Microsystems, a company best known for its high-end UNIX workstations.

Modeled after C++, the Java language was designed to be small, simple, and 

portable across platforms and operating systems, both at the source and at the

binary level, which means that Java programs (applets and applications) can run

on any machine that has the Java virtual machine installed (you'll learn more about this later).

Java is usually mentioned in the context of the World Wide Web, where browsers

such as Netscape's Navigator and Microsoft's Internet Explorer claim to be "Java enabled." 

Java enabled means that the browser in question can download and play Java programs, 

called applets, on the reader's system. Applets appear in a Web page much the same way 

as images do, but unlike images, applets are dynamic and interactive. Applets can be used 

to create animation, figures, forms that immediately respond to input from the reader, games,

or other interactive effects on the same Web pages among the text and graphics.

WEL_COME to java Universe

Hey Dear Welcome To Java World

Here we made this blog to improve your knowledge about
 java programming and help to improve your
computer programming knowledge.......................

Here we are specially going to help our those friends who
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In this blog we started with basic Knowledge to Upgredetion so
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                                 -- SUNIL KUMAR MUKESH KUMAR