Java Variable pro

Java static member variable

public class StaticMemberExample

{

public static void main(String[] args)

{

ObjectCounter object1 = new ObjectCounter();

System.out.println(object1.getNumberOfObjects());

ObjectCounter object2 = new ObjectCounter();

System.out.println(object2.getNumberOfObjects());

  }

}

class ObjectCounter

{

static int counter=0;

public ObjectCounter()

{

counter++;

}

public int getNumberOfObjects()

{

return counter;

   }

}

Java static method

public class StaticMethodExample

{

public static void main(String[] args)

{

int result = MathUtility.add(1, 2);

System.out.println("(1+2) is : " + result);

   }

}

class MathUtility

{

public static int add(int first, int second)

{

return first + second;

   }

}     

 

Java Final variable

public class FinalVariableExample

{   

public static void main(String[] args)

{

 final int hoursInDay=24;

hoursInDay=12;         

System.out.println("Hours in 5 days = " + hoursInDay * 5);

  }

}

Generate Bouncing Lines Using Applet

import java.awt.*;

import java.applet.Applet;

public class BouncingLines extends Applet implements Runnable

          {

Thread runner = null;

final static int Width  = 200;

final static int Height = 100;

Image    image;

Graphics graphics;

int[] x1;

int[] y1;

int[] x2;

int[] y2;

int dx1 = 2 + (int)( 3 * Math.random() );

int dy1 = 2 + (int)( 3 * Math.random() );

int dx2 = 2 + (int)( 3 * Math.random() );

int dy2 = 2 + (int)( 3 * Math.random() );

static int first = 0;

final static int Lines = 50;

public void init()

{

x1 = new int[Lines];

y1 = new int[Lines];

x2 = new int[Lines];

y2 = new int[Lines];

x1[0] = (int)( Width  * Math.random() );

y1[0] = (int)( Height * Math.random() );

x2[0] = (int)( Width  * Math.random() );

y2[0] = (int)( Height * Math.random() );

for ( int i = 1; i < Lines; i++ )

 {

x1[i] = x1[0];

y1[i] = y1[0];

x2[i] = x2[0];

y2[i] = y2[0];

}

image    = createImage( Width, Height );

graphics = image.getGraphics();

} 

public void start()

{

if ( runner == null )

{

runner = new Thread( this );

runner.start();

  }

} 

public void stop()

{

if ( runner != null && runner.isAlive() )

runner.stop();

runner = null;

}

public void run()

{

  

while (runner != null)

{

repaint();

try

{

 Thread.sleep( 20 );

}

catch ( InterruptedException e )

{

}

}

}

public void paint( Graphics g )

{

update( g );

}

public void update( Graphics g )

{

graphics.setColor( Color.black );

graphics.fillRect( 0, 0, Width, Height );

for(int r=4;r<=9;r++)

{

 graphics.setColor( Color.green );

 int line = first;

for ( int i = 0; i < Lines; i++ )

{

 graphics.drawLine( x1[line], y1[line],

x2[line], y2[line] );

line++;

if ( line == Lines ) line = 0;

}

line = first;

first--;

if ( first < 0 ) first = Lines - 1;

  

x1[first] = x1[line];

y1[first] = y1[line];

x2[first] = x2[line];

y2[first] = y2[line];

if (x1[first] + dx2 < Width)

x1[first] += dx1;

else

dx1 = -(2 + (int)( 3 * Math.random() ));

if (x1[first] + dx1 >= 0)

x1[first] += dx1;

else

dx1 = 2 + (int)( 3 * Math.random() );

if (y1[first] + dy1 < Height)

y1[first] += dy1;

else

dy1 = -(2 + (int)( 3 * Math.random() ));

if (y1[first] + dy1 >= 0)

y1[first] += dy1;

else

dy1 = 2 + (int)( 3 * Math.random() );

if (x2[first] + dx2 < Width)

x2[first] += dx2;

else

dx2 = -(2 + (int)( 3 * Math.random() ));

if (x2[first] + dx2 >= 0)

x2[first] += dx2;

else

dx2 = 2 + (int)( 3 * Math.random() );

if (y2[first] + dy2 < Height)

y2[first] += dy2;

else

dy2 = -(2 + (int)( 3 * Math.random() ));

if (y2[first] + dy2 >= 0)

y2[first] += dy2;

else

dy2 = 2 + (int)( 3 * Math.random() );

g.drawImage( image, 0, 0, this );

     }

   }

}

Java Convert int Array to String

import java.util.Arrays;

public class ConvertIntArrayToStringExample

{

public static void main(String args[])

{

int[] intNumbers = new int[]{1, 2, 3, 4, 5};

StringBuffer sbfNumbers = new StringBuffer();

String strSeparator = " ";

if(intNumbers.length > 0)

{

sbfNumbers.append(intNumbers[0]);

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

{

sbfNumbers.append(strSeparator).append(intNumbers[i]);

 }

}

System.out.println("int array converted to String using for loop");

System.out.println(sbfNumbers.toString());

String strNumbers = Arrays.toString(intNumbers);

System.out.println("String generated from Arrays.toString method: " + strNumbers);

strNumbers = strNumbers.replaceAll(", ", strSeparator).replace("[", "").replace("]", "");

System.out.println("Final String: " + strNumbers);

  }

}