Java

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Java is a high-level programming language originally developed by Sun Microsystems and released in 1995. Java runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX. This tutorial gives an initial push to start you with Java. For more detail kindly check tutorialspoint.com/java

What isJava?
Java is:

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Object Oriented Platform independent: Simple Secure Architectural- neutral Portable Robust Multi-threaded Interpreted High Performance Distributed Dynamic

Java Environment Setup:
Java SE is freely available from the link Download Java. So you download a version based on your operating system. You can refere to installation guide for a completedetail.

Java Basic Syntax:
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Object - Objects have states and behaviors. Example: A dog has states-color, name, breed as well as behaviors -wagging, barking, eating. An object is an instance of a class. Class - A class can be defined as a template/ blue print that describe the behaviors/states that object of its type support. Methods - A method is basically a behavior. A class can containmany methods. It is in methods where the logics are written, data is manipulated and all the actions are executed. Instant Variables - Each object has its unique set of instant variables. An object.s state is created by the values assigned to these instant variables.

First Java Program:
Let us look at a simple code that would print the words Hello World.

public class MyFirstJavaProgram{1|Page

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/* This is my first java program. * This will print 'Hello World' as the output */ public static void main(String []args){ System.out.println("Hello World"); // prints Hello World } }
About Java programs, it is very important to keep in mind the following points.

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Case Sensitivity - Java is case sensitive which means identifier Hello andhello would have different meaning in Java. Class Names - For all class names the first letter should be in Upper Case. If several words are used to form a name of the class each inner words first letter should be in Upper Case.

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Example class MyFirstJavaClass Method Names - All method names should start with a Lower Case letter. If several words are used to form the name of the method, theneach inner word's first letter should be in Upper Case.

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Example public void myMethodName() Program File Name - Name of the program file should exactly match the class name. When saving the file you should save it using the class name (Remember java is case sensitive) and append '.java' to the end of the name. (if the file name and the class name do not match your program will not compile).Example : Assume 'MyFirstJavaProgram' is the class name. Then the file should be saved as 'MyFirstJavaProgram.java' public static void main(String args[]) - java program processing starts from the main() method which is a mandatory part of every java program..

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Java Identifiers:
All java components require names. Names used for classes, variables and methods are called identifiers. Injava there are several points to remember about identifiers. They are as follows:

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All identifiers should begin with a letter (A to Z or a to z ), currency character ($) or an underscore (-). After the first character identifiers can have any combination of characters. A key word cannot be used as an identifier. Most importantly identifiers are case sensitive. Examples of legalidentifiers:age, $salary, _value, __1_value Examples of illegal identifiers : 123abc, -salary

Java Modifiers:
Like other languages it is possible to modify classes, methods etc by using modifiers. There are two categories of modifiers.

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Access Modifiers : defualt, public , protected, private

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Non-access Modifiers : final, abstract,...