INTRODUCTION TO JAVA
Java technology is both platform and programming language.
Java is Object Oriented Programming language.
Java was developed by James Gosling and his team at Sun Microsystems lab.
Initially called Oak, in honour of the tree outside Gosling's window, its name was changed to Java because there was already a language called Oak.
Java word doesn't have specific meaning,it refers hot COFFEE.
Coffee Cup is the icon of Java.
Motivation behind developing Java
Java platform was initially developed to address the problems of building software for networked consumer electronic devices e.g.Washing machine,Refrigerator.
To meet that requirement compiled code has to be transported across networks and they should operate on any OS(Operating System).
Before Java, the software for electronic devices was developed by C,C++ and these languages are platform dependent.
So there was a requirement for platform-independent language,that could be used to create software which can be used in any electroninc devices.
At the same time World Wide Web was emerging in the market, So many CPUs of different environment was to be connected.
So there was need for a platform independent & portable language.
So that time only one solution was available JAVA formerly known as Oak.
Features of Java
- Object Oriented
Why to use Java ?
Java is simple, easy to design , easy to write, and therefore easy to compile and debug.
Java is object-oriented, that is used to build modular programs and reusable code in other application.
Java is platform-independent and flexible in nature.
Most significant feature of Java is to run a program easily from one computer system to another.
Java works on distributed environment.
Java is designed to work on distributed computing , any network programs in Java is same as sending and receiving data to and from a file. Java is secure.
Java is secure.
Java language, compiler, interpreter and runtime environment are secure.
Java is robust.
Java emphasis on checking for possible errors, as Java compilers are able to detect many error in program during the execution of respective program.
Java supports multithreading.Multithread is the path of execution for a program to perform several tasks simultaneously within a program.
Java come with the concept of Multithreaded Program.
Why Java is not fully object oriented?
It doesn't support Multiple inheritance.
It allows use of primitive data type which are not an objects.
It allows static methods to call without creating the instance.
Few terminologies related to Java Language
Source Code : Programme written by Developer according to the Java language syntax.
Compiled Code : Compiler generated code that converted from source code.
Compiler : It is programme that converts source code into machine language at once e.g JavaC
Interpreter : It is programme that converts source code into machine language line by line e.g JIT(Just-in-Time)
Abstract Window Toolkit (AWT) : A collection of graphical user interface (GUI) components that were implemented using native-platform versions of the components.
API : Application Programming Interface. The specification of how a programmer writing an application accesses the behaviour and state of classes and objects.
Applet : A program written in the Java(TM) programming language to run within a web browser compatible with the Java platform, such as HotJava(TM) or NetscapeNavigator(TM).
ASCII : American Standard Code for Information Interchange. A standard assignment of 7-bit numeric codes to characters.
Bean : A reusable software component. Beans can be combined to create an application.
Casting : Conversion from one data type to another.
JDK : Java Development Kit
JAR Files (.jar) : Java ARchive. A file format used for aggregating many files into one.
Java Application Environment (JAE) : The source code release of the Java Development Kit (JDK(TM)) software.
JRE : Java(TM) runtime environment.
JVM : Java Virtual Machine.