Java examples

Java is a programming language originally developed by James Gosling at Sun Microsystems (which has since merged into Oracle Corporation) and released in 1995 as a core component of Sun Microsystems Java platform

Few Example programs 

Exception Handling in JAVA

public class S{

   public static void main(String args[]){
      int a[] = new int[2];
      try{
         System.out.println("Access element three :" + a[3]);
      }catch(ArrayIndexOutOfBoundsException e){
         System.out.println("Exception thrown  :" + e);
      }
      finally{
         a[0] = 6;
         System.out.println("First element value: " +a[0]);
         System.out.println("The finally statement is executed");
      }
   }
} 

Crop image in JAVA

import java.awt.*;
import javax.swing.*;
import java.awt.image.CropImageFilter;
import java.awt.image.FilteredImageSource;

public class CropImage extends JFrame {
  Image image;
  Insets insets;

  public CropImage() {
    super("Crop Image");
    ImageIcon icon = new ImageIcon("image4.jpg");
    image = icon.getImage();
    image = createImage(new FilteredImageSource(image.
       getSource(),new CropImageFilter(75, 70, 140, 150)));
  }
  public void paint(Graphics g) {
    super.paint(g);
    if (insets == null) {
      insets = getInsets();
    }
    g.drawImage(image, insets.left, insets.top, this);
  }
  public static void main(String args[]) {
    JFrame frame = new CropImage();
    frame.setSize(250, 250);
    frame.show();
  }
} 

Drag and Drop in JAVA 

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.border.TitledBorder;

public class MouseDragAndDrop extends JFrame {
Canvas1 canvas;
  JLabel label;

  public MouseDragAndDrop() {
    super();
    Container container = getContentPane();
    canvas = new Canvas1();
    container.add(canvas);
    JPanel panel = new JPanel();
    panel.setLayout(new GridLayout(1, 2));
    label = new JLabel("");
    panel.add(label);
    container.add(panel, BorderLayout.SOUTH);
    setSize(600,300);
    setVisible(true);
  }
    public static void main(String arg[]) {
    new MouseDragAndDrop();
  }
  class Canvas1 extends JPanel {
    double p, q, width, height;
    int p1, q1, p2, q2;
    Rectangle2D rect1,rect2;
    Rectangle2D rectangle;
    Cursor cursor;
    public Canvas1() {
      p = 25;
      q = 25;
      width = 90;
      height = 70;
      addMouseListener(new EventMouseListener());
      addMouseMotionListener(new EventMouseMotionListener());
    }
    public void paint(Graphics g) {
      Graphics2D g2 = (Graphics2D) g;
      rect1 = new Rectangle2D.Double(p, q, width, height);
      g2.draw(rect1);
      if (rectangle != null) {
        drawSquares(g2, rectangle);
      }
      if (cursor != null)
        setCursor(cursor);
    }
    public void drawSquares(Graphics2D g2, Rectangle2D rect) {
      double p = rect.getX();
      double q = rect.getY();
      double width = rect.getWidth();
      double height = rect.getHeight();
      g2.setColor(Color.black);
    }
   class EventMouseListener extends MouseAdapter {
      public void mousePressed(MouseEvent event) {
          rect2 = rect1;
          rectangle = rect1.getBounds2D();
          display(rect2);
          p1 = event.getX();
          q1 = event.getY();
      }
      public void mouseReleased(MouseEvent event) {
          rectangle = rect1.getBounds2D();
          rect2 = rect1;
          display(rect2);
       }
      public void mouseClicked(MouseEvent event) {
          rect2 = rect1;
          rectangle = rect1.getBounds2D();
          display(rect2);
        }
   }
    class EventMouseMotionListener extends MouseMotionAdapter {
      public void mouseDragged(MouseEvent event) {
        if (rect1.contains(event.getX(), event.getY())) {
          rectangle = null;
          rect2 = rect1;
          p2 = event.getX();
          q2 = event.getY();
          p = p + p2 - p1;
          q = q + q2 - q1;
          p1 = p2;
          q1 = q2;
        }
        if (rect2 != null)
          display(rect2);
        canvas.repaint();
      }
    public void mouseMoved(MouseEvent event) {
         cursor = Cursor.getPredefinedCursor(Cursor.HAND_CURSOR);
           }
        }
      public void display(Shape shape) {
      double p = rect2.getX();
      double q = rect2.getY();
      double width= rect2.getWidth();
      double height = rect2.getHeight();
      String st = "(" + Double.toString(p)+","+Double.toString(q) + ")";
      String sizeString = "(" + Double.toString(width) + ","+
        Double.toString(height) + ")";
      label.setText(st);
    }
  }
}