load class to applet- load frame class to applet

load class to applet- load frame class to applet with threading.
java code

import java.awt.*;
import java.util.*;
import java.applet.Applet;

public class AppletButton extends Applet implements Runnable {
    int frameNumber = 1;
    String loadedClass;
    String btnString;
    String newTitle;
    int widthVar = 0;
    int heightVar = 0;
    Button button;
    Thread frameThread;
    Label labelObj;
    boolean loadedBoolean = false;

    public void init() {
        loadedClass = getParameter("WINDOWCLASS");
        if (loadedClass == null) {
            loadedClass = "simpleFrame";
        }

        btnString = getParameter("BUTTONTEXT");
        if (btnString == null) {
            btnString = "Click here to bring up a " + loadedClass;
        }

        newTitle = getParameter("WINDOWTITLE");
        if (newTitle == null) {
            newTitle = loadedClass;
        }

        String windowWidthString = getParameter("WINDOWWIDTH");
        if (windowWidthString != null) {
            try {
                widthVar = Integer.parseInt(windowWidthString);
            } catch (NumberFormatException e) {
                //Use default width.
            }
        }
 
        String windowHeightString = getParameter("WINDOWHEIGHT");
        if (windowHeightString != null) {
            try {
                heightVar = Integer.parseInt(windowHeightString);
            } catch (NumberFormatException e) {
                //Use default height.
            }
        }
 
        setLayout(new GridLayout(2,0));
        add(button = new Button(btnString));
        button.setFont(new Font("Arial", Font.PLAIN, 14));

        add(labelObj = new Label("", Label.CENTER));
    }

    public void start() {
        if (frameThread == null) {
            frameThread = new Thread(this, "Bringing Up " + loadedClass);
            frameThread.start();
        }
    }

    public synchronized void run() {
        Class classNameToLoad = null;
        Class tmp = null;
        String name = null;
        
      // Check class
        try {
            classNameToLoad = Class.forName(loadedClass);
        } catch (Exception e) {
            // The specified class isn't anywhere that we can find.
            labelObj.setText("Can't create window: Couldn't find class "
                              + loadedClass);
            button.disable();
            return;
        }

        // Find out whether the class is a Frame.
        for (tmp = classNameToLoad, name = tmp.getName();
             !( name.equals("java.lang.Object") ||
                name.equals("java.awt.Frame") ); ) {
            tmp = tmp.getSuperclass();
            name = tmp.getName();
        }
        if ((name == null) || name.equals("java.lang.Object")) {
          
            labelObj.setText("Can't create window: "
                              + loadedClass +
                          " isn't a Frame subclass.");
            button.disable();
            return;
        } else if (name.equals("java.awt.Frame")) { 
         
            while (frameThread != null) {
                while (loadedBoolean == false) {
                    try {
                        wait();
                    } catch (InterruptedException e) {
                    }
                }

                //We've been asked to bring up a window.
                loadedBoolean = false;
                Frame window = null;
                try {
                    window = (Frame)classNameToLoad.newInstance();
                } catch (Exception e) {
                    labelObj.setText("Couldn't create instance of class "
                                  + loadedClass);
                    button.disable();
                    return;
                }
                if (frameNumber == 1) {
                    window.setTitle(newTitle);
                } else {
                    window.setTitle(newTitle + ": " + frameNumber);
                }
                frameNumber++;

                //Set the window's size.
                window.pack();
                if ((widthVar > 0) | (heightVar > 0)) {
                    window.resize(Math.max(widthVar,
                                           window.size().width),
                                  Math.max(heightVar,
                                           window.size().height));
                }

                window.show();
                labelObj.setText("");
            }
        }
    }
                
    public synchronized boolean action(Event event, Object what) {
        if (event.target instanceof Button) {
            //signal the window thread to build a window
            labelObj.setText("Please wait until we load the class");
            loadedBoolean = true;
            notify();
        } 
        return true;
    }
}

class simpleFrame extends Frame {
    public simpleFrame() {
        resize(400, 400);
    }
}