Name: rlT66838			Date: 06/05/2000


java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-C)
Java HotSpot(TM) Client VM (build 1.3.0-C, mixed mode)

jre 1.3 produces the following error

#
# An EXCEPTION_ACCESS_VIOLATION exception has been detected in native code
outside the VM.
# Program counter=0x5006cecd
#

and jre1.3.0rc1 (distributed with Netscape 6 PR1) produces this error

#
# HotSpot Virtual Machine Error, EXCEPTION_ACCESS_VIOLATION
#
# Error ID: 4F533F57494E13120E43505002BE
#

abnormal program termination

It is generated by this line:
e.startDrag(new Cursor(Cursor.HAND_CURSOR), transferable, sourceHandler);

near the end of this Java program, the DragNDrop application in chapter 16 of
Sams Java 2 Platform Unleashed (a fairly popular book):

import java.awt.*;
import java.awt.event.*;
import java.awt.dnd.*;
import java.awt.datatransfer.*;
import java.io.*;

public class DragNDrop extends Frame {
	int screenWidth = 400;
	int screenHeight = 400;
	Panel panel = new Panel();
	Label topLabel = new Label("Enter text in this text area:");
	Label bottomLabel = new Label("And then drag it to this text area:");
	TextArea textArea1 = new TextArea();
	TextArea textArea2 = new TextArea();

	// Drag and drop variables
	DragSource source = new DragSource();
	DropTarget target = new DropTarget(textArea2, DnDConstants.ACTION_COPY, new DropTargetHandler(), true);
	TextTransfer transferable = new TextTransfer();
	DragSourceHandler sourceHandler = new DragSourceHandler();

	public static void main(String args[]) {
		DragNDrop app = new DragNDrop();
	}

	public DragNDrop() {
		super("DragNDrop");
		setup();
		setSize(screenWidth, screenHeight);
		addWindowListener(new WindowEventHandler());
		show();
	}

	void setup() {
		target.setActive(true);
		panel.setLayout(new GridLayout(4, 1));
		panel.add(topLabel);
		panel.add(textArea1);
		Toolkit toolkit = Toolkit.getDefaultToolkit();
		try {
		toolkit.createDragGestureRecognizer(Class.forName("java.awt.dnd.MouseDragGesture Recognizer"),
				source, textArea1, DnDConstants.ACTION_COPY, new DragHandler());
		}
		catch (ClassNotFoundException ex) {
			System.out.println("Recognizer class not found.");
			System.exit(0);
		}
		panel.add(bottomLabel);
		panel.add(textArea2);
		add("Center", panel);
	}

	class DragSourceHandler implements DragSourceListener {
		public void dropActionChanged(DragSourceDragEvent ev) {
			System.out.println("Source: Drop action changed");
		}

		public void dragEnter(DragSourceDragEvent ev) {
			System.out.println("Source: Drag enter");
		}

		public void dragOver(DragSourceDragEvent ev) {
		}

		public void dragExit(DragSourceEvent ev) {
			System.out.println("Source: Drag exit");
		}

		public void dragDropEnd(DragSourceDropEvent ev) {
			System.out.println("Source: Drag drop end");
		}
	}

	class DropTargetHandler implements DropTargetListener {
		public void dragEnter(DropTargetDragEvent ev) {
			System.out.println("Target: Drag enter");
			DataFlavor df[] = ev.getCurrentDataFlavors();
			for (int i = 0; i < df.length; i++) {
				if (df[i].equals(DataFlavor.plainTextFlavor) ||
					df[i].equals(DataFlavor.stringFlavor)) {
					ev.acceptDrag(DnDConstants.ACTION_COPY);
					return;
				}
			}
			ev.rejectDrag();
		}

		public void dragOver(DropTargetDragEvent ev) {
		}

		public void dragExit(DropTargetEvent ev) {
			System.out.println("Target: Drag exit");
		}

		public void dropActionChanged(DropTargetDragEvent ev) {
			System.out.println("Target: Drop action changed");
		}

		public void drop(DropTargetDropEvent ev) {
			System.out.println("Target: Dropped");
			ev.acceptDrop(DnDConstants.ACTION_COPY);
			Transferable transfer = ev.getTransferable();
			DataFlavor df[] = ev.getCurrentDataFlavors();
			String input = "";
			try {
				for (int i = 0; i < df.length; i++) {
					if (df[i].equals(DataFlavor.stringFlavor) ||
					df[i].equals(DataFlavor.plainTextFlavor)) {
						input = (String) transfer.getTransferData(df[i]);
					}
				}
				textArea2.setText(input);
			}
			catch (Exception e) {
				System.out.println(e.toString());
			}
			try {
			        target.getDropTargetContext().dropComplete(true);
			}
			catch (Exception e) {
			}
		}
	}

	class TextTransfer implements Transferable {
		public DataFlavor[] getTransferDataFlavors() {
			DataFlavor flavors[] = new DataFlavor[1];
			flavors[0] = DataFlavor.plainTextFlavor;
			return flavors;
		}

		public boolean isDataFlavorSupported(DataFlavor flavor) {
			return (flavor.equals(DataFlavor.plainTextFlavor));
		}

		public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
			return textArea1.getText();
		}
	}

	class DragHandler implements DragGestureListener {
		public void dragGestureRecognized(DragGestureEvent e) {
			e.startDrag(new Cursor(Cursor.HAND_CURSOR), transferable, sourceHandler);
		}
	}

	class WindowEventHandler extends WindowAdapter {
		public void windowClosing(WindowEvent e) {
			System.exit(0);
		}
	}
}


(Review ID: 105662) 
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