array in java

array in java :: futureX

In java,array is an object. Array in C & C++ is static but in Java it is dynamic.

1D Array:


Declaration:

datatype  []var = new datatype[size];
                      OR
datatype[]  var = new datatype[size];
                      OR
datatype  var[] = new datatype[size]; 

Example:


class A{
public static void main(String[] args){
int a[]=new int[5];
a[0]=11;
a[2]=33;
a[4]=1;

for(int i=0;i<a.length;i++)
System.out.println(a[i]);
}
}

Output:(default value is zero)

11

0

33

0

1

Q: Write a program to find minimum from the Array?

class A{

static void printmin(int arr[]){

int min=arr[0];

for(int i=1;i<arr.length;i++)

{

if(min>arr[i])

min=arr[i];

}

System.out.println("min is ::" +min);

}

public static void main(String[] args){

int a[]=new int[5];

a[0]=12;

a[1]=1;

a[2]=22;

a[3]=5;

a[4]=32;

printmin(a);

}}

2D Array:

Declaration:

datatype[][]  var = new datatype[size][size];
                      OR
datatype  [][]var = new datatype[size][size];
                      OR
datatype var[][] = new datatype[size][size];
                      OR
datatype  []var[] = new datatype[size][size];

Example:


class A{
public static void main(String args[]){
int a[][]=new int[3][3];
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++){
a[i][j]=i+j;
System.out.println(a[i][j]+" ");
}
System.out.println();
}}}

Anonymous Array:
JAVA feature of array. 
In normal array, as int a[]={} same array can't declared twice. 

class A{
static void printarray(int arr[]){
for(int i=0;i<arr.length;i++)
{
System.out.println(arr[i]);
}
}
public static void main(String args[]){
printarray(new int[]{14,5,5,8});
printarray(new int[]{14,3,8,8});
}}

                                             JAVA TUTORIALS HOMEPAGE

access modifiers in java

access modifiers in java :: futureX

 There are 4 types of access modifiers:

1. private
2. default
3. protected
4. public

Private :
The private access modifier is accessible only within class.

example :

class Emp{
private int id;
private void show(){System.out.println(id);}
}

class Test{
public static void main(String args[]){
Emp e=new Emp();
e.id=10;
e.show();
}
}

output:compile time error


Note: A class cannot be private or protected except nested class.


Default :
If you don't use any modifier, it is treated as default modifier by default. The default modifier is accessible only within package.

example:

//save as A.java
package com.futurex;
public class A{
void msg(){System.out.println("hello");}
}

//save as Test.java

package com.techshakti;

import com.futurex.*;

class Test{

public static void main(String args[]){

A a=new A();

a.msg();

}

}

output: msg() is not public in A; cannot be accessed from outside package

Protected :
The protected access modifier is accessible within package and outside the package by only through inheritance.
The protected access modifier can be applied on the data member, method and constructor. It can't be applied on the class.

example:

//save as A.java
package com.futurex;
public class A{
protected void msg(){System.out.println("hello");}
}

//save as Test.java

package com.techshakti;

import com.futurex.*;

class Test extends A{

public static void main(String args[]){

Test t=new Test();

t.msg();

}

}

Public:
The public access modifier is accessible everywhere. It has the widest scope among all other modiers.

example:

//save as A.java
package pack;
public class A{
public void msg(){System.out.println("Hello");}
}


//save as B.java
package mypack;
import pack.*;

class B{
  public static void main(String args[]){
   A obj = new A();
   obj.msg();
  }
}


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basics of HTML

basic HTML :: futureX

HTML Headings


HTML headings are defined with the <h1> to <h6> tags.

Example

<h1>This is a heading</h1>
<h2>This is a heading</h2>
<h3>This is a heading</h3>

html heading example :: futureX

HTML Paragraphs

HTML paragraphs are defined with the <p> tag.

Example

<p>This is a paragraph.</p>
<p>This is another paragraph.</p>

HTML Links

HTML links are defined with the <a> tag.

Example

<a href="http://www.futurextech.blogspot.com">This is a link</a>



Note: The link address is specified in the href attribute.


HTML Images

HTML images are defined with the <img> tag.

Example

<img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXGB1U7-60jnOvecQdP_Wqk5F3kJ5OOZOwAvC0zv-vkpHpIRIUBK68VzbvpdECUHAqRJz-84xpM9hupSCiT-GrD6zpDZVn6_UozjhTF6TBKhTshuAj8TPm9RLnug7nT5szSb3p8O3WMLfY/s1600/images.jpg" width="104" height="142">


Note: The filename and the size of the image are provided as attributes.

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Package and subpackages in java

A package is a group of similar types of class, interfaces and sub-packages.
Package can be categorized in two form, built-in package and user-defined package. There are many built-in packages such as java.lang, awt, javax, swing, net, io, util, sql etc.

package in java :: futureX

In this page, we will have the detailed learning of creating user-defined packages.

Advantage of Package

• Package is used to categorize the classes and interfaces so that they can be easily maintained.
• Package providEs access protection.
• Package removes naming collision.

Example

To compile : javac -d . Simple.java
To run       : java mypack.Simple

package com;
class Simple{
public static void main(){
System.out.println("hello java");
}
}

The -d is a switch that tells the compiler where to put the class file i.e. it represents destination. The . represents the current folder.


How to access package from another package?

• import package.*;
• import package.classname;
• fully qualified name.

The import keyword is used to make the classes and interface of another package accessible to the current package.

If you use package.* then all the classes and interfaces of this package will be accessible but not subpackages.

If you import package.classname then only declared class of this package will be accessible but not subpackages.

If you use fully qualified name then only declared class of this package will be accessible. Now there is no need to import. But you need to use fully qualified name every time when you are accessing the class or interface.

package math;
public class Calc{
public static int cube(int n){return n*n*n;}
}


//import all the classes of that package

package com;
import math.*;
class Simple{
public static void main(String args[]){
System.out.println(Calc.cube(5));
}
}

//only declared class is acessible

package com;
import math.Calc;
class Simple{
public static void main(String args[]){
System.out.println(Calc.cube(5));
}
}




//without import, full qualified name

package com;
class Simple{
public static void main(String args[]){
System.out.println(math.Calc.cube(5));
}
}


Subpackages:

Package inside the package is called the subpackage. It should be created to categorize the package further. Let's take an example, Sun Microsystems has defined a package named java that contains many classes like System, String, Reader, Writer, Socket etc. These classes represent a particular group e.g. Reader and Writer classes are for Input/Output operation, Socket and ServerSocket classes are for networking etc and so on. So, Sun has subcategorized the java package into subpackages such as lang, net, io etc. and put the Input/Output related classes in io package, Server and ServerSocket classes in net packages and so on.

standard declaration:
com.companyname.packagename.classname

package com.techshakti.math;
public class subpackage{
public static int cube(int n){return n*n*n;}
}


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Abstraction in java (interface class)

interface in java :: futureX

Interface: An interface is a blueprint of a class. It has static constants and abstract methods.
The interface is a mechanism to achieve abstraction in java. There can be only abstract methods in the interface. It is used to achieve fully abstraction and multiple inheritance in Java.

Why use Interface?

It is used to achieve fully abstraction.
By interface, we can support the functionality of multiple inheritance.
It can be used to achieve loose coupling
the java compiler converts methods of interface as public and abstract, data members as public,final and static by default.

Example :

interface Shape{
void draw();
}

class Circle implements Shape{
public void draw(){System.out.println("drawing circle");}
}

class Rectangle implements Shape{
public void draw(){System.out.println("drawing rectangle");}
}

class Test{
public static void main(String args[]){
Shape S=new Circle();
S.draw();

}}

multiple inheritance by interface :

interface Shape{
void draw();
}

interface Color{
String getColor();
}


class Rectangle implements Shape,Color{
public void draw(){System.out.println("drawing rectangle");}
public String getColor(){return("red");}
}

class Test{
public static void main(String args[]){
Rectangle s=new Rectangle();
s.draw();
System.out.println(s.getColor());
}}

                                            JAVA TUTORIALS HOMEPAGE

Abstraction in java (abstract class)

abstraction in java :: futureX

Abstraction is a process of hiding the implementation details and showing only functionality to the user.Abstraction lets you focus on what the object does instead of how it does it.


Ways to achieve Abstraction:
Abstract class (0 to 100%)
Interface (100%)

Abstract class:
A class that is declared as abstract is known as abstract class.It needs to be extended and its method implemented.It cannot be instantiated.


           abstract class class_name{}

Abstract method:
A method that is declared as abstract and does not have implementation is known as abstract method.


          abstract return_type method_name();    //no braces{}

Example:

abstract class Shape{
abstract void draw();
}

class Rectangle extends Shape{
void draw(){System.out.println("drawing rectangle");}
}

class Circle extends Shape{
void draw(){System.out.println("drawing circle");}
}

class Test{
public static void main(String args[]){
Shape s=new Circle();
s.draw();
}
}


Note: An abstract class can have data member,abstract method,method body,constructor and even main() method.

Rule: If there is any abstract method in a class, that class must be abstract.

//Shape is not abstract and does not override abstract method //draw() in shape

class Shape{
abstract void draw();
}


                   JAVA TUTORIALS HOMEPAGE

Introduction to HTML

What is HTML?

indroduction to HTML :: futureX

• HTML is a language for describing web pages.
• HTML stands for Hyper Text Markup Language
• HTML is a markup language
• A markup language is a set of markup tags
• The tags describes document content
• HTML documents contain HTML tags and plain text
• HTML documents are also called web pages

HTML Tags

• HTML markup tags are usually called HTML tags
• HTML tags are keywords (tag names) surrounded by angle brackets like <html>
• HTML tags normally come in pairs like <b> and </b>
• The first tag in a pair is the start tag, the second tag is the end tag
• The end tag is written like the start tag, with a forward slash before the tag name
• Start and end tags are also called opening tags and closing tags

                                      <tagname>content</tagname>


HTML Elements

"HTML tags" and "HTML elements" are often used to describe the same thing.
But strictly speaking, an HTML element is everything between the start tag and the end tag, including the tags.
               <p>This is a paragraph.</p>


Web Browsers

The purpose of a web browser (such as Google Chrome, Internet Explorer, Firefox, Safari) is to read HTML documents and display them as web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page.

HTML Versions

Since the early days of the web, there have been many versions of HTML:
Version                        Year
HTML                          1991
HTML+                        1993
HTML 2.0                    1995
HTML 3.2                    1997
HTML 4.01                  1999
XHTML 1.0                  2000
HTML5                        2012
XHTML5                      2013

The <!DOCTYPE> Declaration

The <!DOCTYPE> declaration helps the browser to display a web page correctly.
There are many different documents on the web, and a browser can only display an HTML page 100% correctly if it knows the HTML type and version used.

Common Declarations

HTML5

<!DOCTYPE html>

HTML 4.01

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">

XHTML 1.0

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

For a complete list of document type declarations, go to our DOCTYPE Reference.

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run time polymorphism

runtime polymorphism in java :: futureX

Runtime polymorphism or dynamic method dispatch is a process in which a call to an overridden method is resolved at runtime rather than at compile-time.In this process, an overridden method is called through the reference variable of a superclass. The determination of the method to be called is based on the object being referred to by the reference variable.


UPCASTING :
When reference variable of Parent class refers to the object of Child class, it is known as upcasting.

upcasing in java :: futureX

For example:

class Animal{
void eat(){System.out.println("eating food");}
}

class Human extends Animal{
void eat(){System.out.println("eating delicious food");}

public static void main(String args[]){
Animal A=new Human();
A.eat();
}
}

Example of runtime polymorphism

class Bike{

   void run(){System.out.println("running");}

 }

 class Splender extends Bike{

   void run(){System.out.println("running safely with 60km");}

   public static void main(String args[]){

     Bike b = new Splender();//upcasting

     b.run();

   }

 }

In this example, we are creating two classes Bike and Splendar. Splendar class extends Bike class and overrides its run() method. We are calling the run method by the reference variable of Parent class. Since it refers to the subclass object and subclass method overrides the Parent class method, subclass method is invoked at runtime. Since it is determined by the compiler, which method will be invoked at runtime, so it is known as runtime polymorphism.


Rule: Runtime polymorphism can't be achieved by data members.

class Bike{ int speedlimit=90; } class Honda extends Bike{ int speedlimit=150; public static void main(String args[]){ Bike obj=new Honda(); System.out.println(obj.speedlimit);//output 90 } }

JAVA TUTORIALS HOMEPAGE

the final keyword

The final keyword in java is used to restrict the user. The final keyword can be used in many context. Final can be:

final keyword in java :: futureX

• variable
• method
• class

Final variable :
If you make any variable as final, you cannot change the value of final variable(It will be constant).

//can't assign a value to final variable class Simple{ final int a=50; void change(){ a=100; //CTE } public static void main(String args[]){ Simple S=new Simple(); S.change(); System.out.println(S.a); } }

Final method :

If you make any method as final, you cannot override it.

//overriden method is final CTE class A{ final void m(){System.out.println("hello");} } class Simple extends A{ void m(){System.out.println("java");} public static void main(String args[]){ Simple S=new Simple(); S.m(); } }

Final class :

If you make any class as final, you cannot inherit it.

//cant inherit from final class CTE final class A{} class Simple extends A{ public static void main(String args[]) {} }

Java tutorials homepage

the super keyword

super is a reference variable that is used to refer immediate parent class object.

Uses of super Keyword:

• super is used to refer immediate parent class instance variable.
• super() is used to invoke immediate parent class constructor.
• super is used to invoke immediate parent class method.

1.super is used to refer immediate parent class instance variable.

Problem without super keyword

class Vehicle{ int speed=50; } class Bike extends Vehicle{ int speed=100; void display(){ System.out.println(speed);//will print speed of Bike } public static void main(String args[]){ Bike b=new Bike(); b.display(); } }

In the above example Vehicle and Bike both class have a common property speed. Instance variable of current class is refered by instance bydefault, but I have to refer parent class instance variable that is why we use super keyword to distinguish between parent class instance variable and current class instance variable.

Solution by super keyword

class Vehicle{ int speed=50; } class Bike extends Vehicle{ int speed=100; void display(){ System.out.println(super.speed);//will print speed of Vehicle now } public static void main(String args[]){ Bike b=new Bike(); b.display(); } }

2.super is used to invoke parent class constructor.

class Vehicle{ Vehicle(){System.out.println("Vehicle is created");} } class Bike extends Vehicle{ Bike(){ super();//will invoke parent class constructor System.out.println("Bike is created"); } public static void main(String args[]){ Bike b=new Bike(); } }

3. super can be used to invoke immediate parent class method.

class Person{ void message(){System.out.println("welcome");} } class Student extends Person{ void message(){System.out.println("welcome to java");} void dislay(){ message();//will invoke current class message() method super.message();//will invoke parent class message() method } public static void main(String args[]){ Student s=new Student(); s.display(); } }

JAVA TUTORIALS HOMEPAGE

Pulmon 2.0 ::Windows 8 Start Screen for Windows

Pulmon is a great application which brings Windows 8 like Metro UI Widgets in Windows 7. It gives you various options to add as tiles such as Mozilla Aurora, Storage etc. Mozilla Aurora widget adds a beautiful tile on desktop. Clicking on it will open Aurora. 

Updates in Pulmon 2.0:

1)Splash Screen has been added to Pulmon. Now Pulmon will start with a metro splash screen

2)Changed Background – Background color of Pulmon has been changed to the metro color “Dodger Blue”

3)They worked on Pulmon 2.0 a lot and fixed some issues

4)Metro UI Colors –  tried their best to select master Metro UI colors for tiles. Now tiles have Metro UI colors

5)Improved Stability – In the previous release, Microsoft Office Suite Tile and BUILD Tile were unstable. But now they are stable and can be used as you use other tiles

6)It have added a “Get Involved!” button in Pulmon to directly involve in Pulmon Project. By pressing this button, Pulmon will open the default E-mail client. You, then, can send us a mail about involvation

7)The sizes of tiles have been decreased to increase flexibility for the users

8)It have implented Windows 8 style tiles e.g. Internet Explorer, Control Panel and BUILD tiles

9)Now the default background is of Windows 8 default start screen background

10)You will get a Metro Menu in fullscreen mode. Just click on User Avatar and see the action. It offers to restart and shutdown the computer and it also offers to change user avatar

11)Storage tile has been updated and now you can select any drive by using Storage Options in right click menu

“12)Zuro” tile is a new tile for Pulmon. It opens Zuro (A web browser based on Metro UI and Immersive UI) when a user double-click on it

13)“Desktop” tile shows the current desktop background

14)Added error handling code for the exceptions

15)“Mozilla Firefox” tile is now “Mozilla Aurora” tile. Works only with Mozilla’s Aurora Channel

16)They have updated Shutdown Manager tile and System Information tile. They were looking ugly but now they are looking very good with a brand new look.

17)It just fixed some tool-tip issues

18)It applied Metro UI on Storage Settings and Zuro Settings.

Note: Below are mentioned only few widgets. The newest version has more widgets than the described below. 

Widgets: 

User- Clicking “User” tile will open a User Widget. If you want to open User Accounts, double-click on the green place of tile or double-click on User Avatar. There are many tweaks available for user tile. Right click on the tile and click options. You can choose “Take User Avatar from Windows System” or choose custom avatar.

Control Panel- Clicking Control Panel tile will load control panel widget. You can open Control Panel by clicking on its tile. Its currently not more than a tile. It will get some features in next versions.

Clock- Pulmon will provide you a very cool widget “Clock”. It will show you time, month and day of the week. Some new tweaks will be provided to you in the next versions

Shutdown Manager- It’s a very easy to use widget which will allows you to control over you pc with one click.Shutdown,Restart, Log Off and Hibernate’s Options are given. Please note that  some of the features are not working.

Webby- Webby is another good widget which provides you quick access to tech sites like The Windows Club, IntoWindows,WinMatrix, AskVG etc.. 

How to Use:

1.Download and Run the application

2.You will see two groups “Add Tiles” and “Remove Tiles”

3.Click a tile in Add Tiles group e.g Control Panel Tile

4.It will load Control Panel tile and the icon of Control Panel will be disappeared from “Add Tiles” group and start appearing in “Remove Tiles” group

5.Click the Control Panel tile in Remove Tiles group will remove it  

 Download Pulmon 2.0 

inheritance in java

Inheritance is a mechanism in which one object acquires all the properties and behaviour of another object. The idea behind inheritance is that you can create new classes that are built upon existing classes. When you inherit from an existing class, you reuse (or inherit) methods and fields, and you add new methods and fields to adapt your new class to new situations.Inheritance represents the IS-A relationship.

Why use Inheritance?

• for method overriding
• for code reusability

Syntax of Inheritance

class Subclass-name  extends Superclass-name

{

//methods and fields

}

The keyword extends indicates that you are making a new class that derives from an existing class.

In the terminology of Java, a class that is inherited is called a superclass. The new class is called a subclass.

types of inheritance:

 example of single level inheritance :

class Animal{

void eat(){System.out.println("eating food");}

}

class Dog extends Animal{

void bark(){System.out.println("barking");}

public static void main(String args[]){

Dog d=new Dog();

d.bark();

d.eat();

}

}

Que) Why multiple inheritance is not supported in java?   To reduce the complexity and simplify the language,multiple inheritance is not supported in java.

                            JAVA TUTORIALS HOMEPAGE

apple iPhone 5 review

Behold, the iPhone 5 is here.

Apple Inc. today announced its new iPhone, as well as changes to its iPod line and iTunes software, at a press event in San Francisco.

In short, the "world's thinnest smartphone" is a whole new phone, matching many of the rumors that had been floating around about its introduction for months.

"We have updated every aspect of iPhone 5," said Phil Schiller, Apple's senior vice president of worldwide marketing. "The challenge is to make it better and smaller."


Features :

The iPhone 5 is lighter and faster -- though also taller -- than any of Apple's previous smartphones. It has a 4-inch screen with an 1136x640 resolution Retina display. It is 7.6 mm thick and weighs in at 112 grams. That's a half-inch bigger, 18 percent thinner, and 20 percent lighter than the iPhone 4S.

Apple said the iPhone 5 has a fifth row of icons on its screen, which features 44 percent more color saturation. A more powerful A6 processor will make the new phone twice as fast as the iPhone 4S. It also has a bumped-up audio system and an upgraded iSight camera. While it remains an 8-megapixel camera, the same as what you find in the iPhone 4S, the iPhone 5's camera will have new better low-light capabilities and a panorama mode, Apple said.

The iPhone 5's battery will "exceed battery life of the iPhone 4s," Schieller said, with eight hours' talk time and 225 hours on standby.

Available in slate and black, or silver and white, the iPhone 5 is made out of glass and alumnium. The back of the phone is all metal -- a change from the iPhone 4S, which had a glass back that, users complained, shattered easily. The phone also comes with a new, smaller cable connector, called Lightning, which is designed to work with more iPhone accessory makers. An adapter will be available for users with older Apple hardware.

Prices :

What will this cost? Apple said the iPhone 5 will sell for $199, $299 and $399 for the 16GB, 22GB and 64GB devices, respectively, with new carrier contracts. The iPhone 4S with 16GB device of memory drops to $99 with a new contract. The iPhone 4 with 8GB is now free on a new contract.

Pre-order sales start on Sept. 14. Apple said the new phones would start to ship on Sept. 21.

The iPhone 5 will have an LTE data connection -- also known as 4G -- and will be available through Verizon, Sprint, AT&T in the United States, as well as other carriers around the world.

The new phone will run Apple's iOS 6, which the company showed off in June at its Worldwide Developers Conference.

"iPhone 5 and iOS 6: the biggest things to happen to iPhone since the iPhone," said Apple CEO Tim Cook.

The iOS 6 has a range of new features, including Apple's own homebrewed maps app (which will replace Google Maps), Facebook integration and a new passbook app, which organizes airplane tickets, coupons and other passes users might have. Siri was also upgraded to launch apps, recommend movies, check on restaurant reservations and update your Facebook status.

The improved graphics will please everyone from the serious gamer to the average app user, said Apple executives. With 700,000 apps currently in the App Store, Apple said all apps have been updated to take advantage of the bigger screen and better graphics.

"The average customer is using more than 100 apps," said Cook.

YouTube is not preloaded with the new software, but Google has released a new iPhone YouTube app one can download.

Demand for the phone announced today was clearly high. Sites like Gazelle and Glyde, which buy older iPhones, have seen a huge surge in traffic over the last few days as people try to unload their phones before they switch to the new one. Some analysts predict the company could sell over 10 million phones in its first month on the market. Apple noted on its last earnings call that it saw a significant drop in iPhone sales in recent months as consumers waited for the new phone.