Java Tutorial 1


Java Tutorial 1
(Java Environment Setup together with Write First Java Program)
> Download Java (JDK) Software together with Install

> laid upward Environment Variable (Path Variable)
(* If desire to execute Java programs from whatsoever directory inwards C Drive)

How to laid upward Path Environment Variable:
OS: Windows 7

> Select MYComputer together with Right click

> Properties

> Advanced System Settings

> Environment Variables

> Select "New" inwards System variables

> Enter Variable every 2nd "Path"

> Enter JDK bin directory path ("C:\Program Files\Java\jdk1.8.0_45\bin") inwards value field

> OK > OK > Ok
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Verify the Environment setup:
> Launch Command Prompt

> Type coffee (It provides details)
-------------------------------------
Three steps to write together with execute Java Programs

i) Write Java Program inwards Notepad (Editor)

ii) Compile the Program (It creates Class file)

Command prompt > Change to Program file Directory

> Type javac Programname.java (java is extension of Java program, javac ascendence for compilation)

iii) Run /Execute the Java Program

> Type coffee programName
(It provides Output on the console)
-----------------------------------------------------
Use Eclipse IDE to write together with execute Java programs.
Eclipse IDE (Integrated Development Environment)

It is a platform to write together with execute Java programs, Perl, Python, PHP, Ruby etc...

It provides Editor, context help, assist for syntax errors, Auto compilation together with debugging.
-----------------------------
Download Eclipse software together with extract.

Steps:
----------------
> Create Java Project
    -> Create a Package
        -> Create a Class / Interface
(We tin plough over notice write coffee code inwards the Class file)
--------------------------------------

Ex:
public shape Sample {
    populace static void principal (String [] args){
        System.out.println("Hello Java together with Selenium");
    }
}
-------------------------------------------------
Java Program construction or Java Syntax:
 

1) Package annunciation statement
ex:

package abcd;
--------------------------------
2) Import statements
we tin plough over notice import Built inwards together with User defined Libraries using import keyword.
(In lodge to purpose Existing Classes, Objects, together with Methods)


Example:

import java.io.console;

(It Imports Console Class alone from io package)

import java.io.*;

(It imports all classes from io package)
------------------
java - project

io - package

Console - Class
----------------------------------------------
3) Class annunciation statement
ex:

public shape Sample {
}

public - Access Modifier

class - Java keyword to declare a class

Sample - Name of the Class

Note: First missive of the alphabet of Class lift should live upper case.
-------------------------------------------------
4) Comments section
// This is a Sample Java Program
-----------------------------------
5) Main Method  

(Java programme execution starts from principal method.)
(Main method is mandatory inwards every Java program)

public static void principal (String [] args) {
}

public - Access Modifier

static - purpose principal method without invoking whatsoever object.

void - returns nothing

main - method name
-------------------------------------------
6) Declarations
We tin plough over notice declare variables together with constants
-----------------------------
Normal statements

Conditional blocks

Loop blocks

Method declarations

Etc...
-----------------------------
Sample Java Program:
package abcd;

import java.io.Console;
import java.lang.*;

public shape Sample2 {
    // This is a Sample Java Program
    populace static void principal (String [] args){
        int a = 50, b, c; // Declaration of Variables
        b= 20; // Initialization
        System.out.println(a + b); // 70
        System.out.println("Addition of a, b is: "+ (a+b));
        lastly int MONEY = 100; // Declaration of Constant
       
        if (a > b) {
            System.out.println("A is a Big Number");
        }
        else
        {
            System.out.println("B is a Big Number");
        }   
       
        for (c = 1; c <= 10; c++){
            System.out.println(c);
        }
        }
    }

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