请教一applet技术问题,急救

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;
import java.util.Date;
import javax.swing.*;
import javax.swing.border.EtchedBorder;
import javax.swing.border.TitledBorder;/**
* Tracks Memory allocated & used, displayed in graph form.
*/
public class MemoryMonitor extends JPanel {   static JCheckBox dateStampCB = new JCheckBox("Output Date Stamp");
   public Surface surf;
   JPanel controls;
   boolean doControls;
   JTextField tf;   public MemoryMonitor() {
       setLayout(new BorderLayout());
       setBorder(new TitledBorder(new EtchedBorder(), "Memory Monitor"));
       add(surf = new Surface());
       controls = new JPanel();
       controls.setPreferredSize(new Dimension(135,80));
       Font font = new Font("serif", Font.PLAIN, 10);
       JLabel label = new JLabel("Sample Rate");
       label.setFont(font);
       label.setForeground(Color.black);
       controls.add(label);
       tf = new JTextField("1000");
       tf.setPreferredSize(new Dimension(45,20));
       controls.add(tf);
       controls.add(label = new JLabel("ms"));
       label.setFont(font);
       label.setForeground(Color.black);
       controls.add(dateStampCB);
       dateStampCB.setFont(font);
       addMouseListener(new MouseAdapter() {
           public void mouseClicked(MouseEvent e) {
              removeAll();
              if ((doControls = !doControls)) {
                  surf.stop();
                  add(controls);
              } else {
                  try {
                      surf.sleepAmount = Long.parseLong(tf.getText().trim());
                  } catch (Exception ex) {}
                  surf.start();
                  add(surf);
              }
              validate();
              repaint();
           }
       });
   }
   public class Surface extends JPanel implements Runnable {       public Thread thread;
       public long sleepAmount = 1000;
       private int w, h;
       private BufferedImage bimg;
       private Graphics2D big;
       private Font font = new Font("Times New Roman", Font.PLAIN, 11);
       private Runtime r = Runtime.getRuntime();
       private int columnInc;
       private int pts[];
       private int ptNum;
       private int ascent, descent;
       private float freeMemory, totalMemory;
       private Rectangle graphOutlineRect = new Rectangle();
       private Rectangle2D mfRect = new Rectangle2D.Float();
       private Rectangle2D muRect = new Rectangle2D.Float();
       private Line2D graphLine = new Line2D.Float();
       private Color graphColor = new Color(46, 139, 87);
       private Color mfColor = new Color(0, 100, 0);
       private String usedStr;
            public Surface() {
           setBackground(Color.black);
           addMouseListener(new MouseAdapter() {
               public void mouseClicked(MouseEvent e) {
                   if (thread == null) start(); else stop();
               }
           });
       }       public Dimension getMinimumSize() {
           return getPreferredSize();
       }       public Dimension getMaximumSize() {
           return getPreferredSize();
       }       public Dimension getPreferredSize() {
           return new Dimension(135,80);
       }
       public void paint(Graphics g) {           if (big == null) {
               return;
           }           big.setBackground(getBackground());
           big.clearRect(0,0,w,h);           float freeMemory = (float) r.freeMemory();
           float totalMemory = (float) r.totalMemory();           // .. Draw allocated and used strings ..
           big.setColor(Color.green);
           big.drawString(String.valueOf((int) totalMemory/1024) + "K allocated",  4.0f, (float) ascent+0.5f);
           usedStr = String.valueOf(((int) (totalMemory - freeMemory))/1024)
               + "K used";
           big.drawString(usedStr, 4, h-descent);           // Calculate remaining size
           float ssH = ascent + descent;
           float remainingHeight = (float) (h - (ssH*2) - 0.5f);
           float blockHeight = remainingHeight/10;
           float blockWidth = 20.0f;
           float remainingWidth = (float) (w - blockWidth - 10);           // .. Memory Free ..
           big.setColor(mfColor);
           int MemUsage = (int) ((freeMemory / totalMemory) * 10);
           int i = 0;
           for ( ; i < MemUsage ; i++) {
               mfRect.setRect(5,(float) ssH+i*blockHeight,
                               blockWidth,(float) blockHeight-1);
               big.fill(mfRect);
           }           // .. Memory Used ..
           big.setColor(Color.green);
           for ( ; i < 10; i++)  {
               muRect.setRect(5,(float) ssH+i*blockHeight,
                               blockWidth,(float) blockHeight-1);
               big.fill(muRect);
           }           // .. Draw History Graph ..
           big.setColor(graphColor);
           int graphX = 30;
           int graphY = (int) ssH;
           int graphW = w - graphX - 5;
           int graphH = (int) remainingHeight;
           graphOutlineRect.setRect(graphX, graphY, graphW, graphH);
           big.draw(graphOutlineRect);           int graphRow = graphH/10;           // .. Draw row ..
           for (int j = graphY; j <= graphH+graphY; j += graphRow) {
               graphLine.setLine(graphX,j,graphX+graphW,j);
               big.draw(graphLine);
           }

           // .. Draw animated column movement ..
           int graphColumn = graphW/15;           if (columnInc == 0) {
               columnInc = graphColumn;
           }           for (int j = graphX+columnInc; j < graphW+graphX; j+=graphColumn) {
               graphLine.setLine(j,graphY,j,graphY+graphH);
               big.draw(graphLine);
           }
--columnInc;           if (pts == null) {
               pts = new int[graphW];
               ptNum = 0;
           } else if (pts.length != graphW) {
               int tmp[] = null;
               if (ptNum < graphW) {
                   tmp = new int[ptNum];
                   System.arraycopy(pts, 0, tmp, 0, tmp.length);
               } else {
                   tmp = new int[graphW];
                   System.arraycopy(pts, pts.length-tmp.length, tmp, 0, tmp.length);
                   ptNum = tmp.length - 2;
               }
               pts = new int[graphW];
               System.arraycopy(tmp, 0, pts, 0, tmp.length);
           } else {
               big.setColor(Color.yellow);
               pts[ptNum] = (int)(graphY+graphH*(freeMemory/totalMemory));
               for (int j=graphX+graphW-ptNum, k=0;k < ptNum; k++, j++) {
                   if (k != 0) {
                       if (pts[k] != pts[k-1]) {
                           big.drawLine(j-1, pts[k-1], j, pts[k]);
                       } else {
                           big.fillRect(j, pts[k], 1, 1);
                       }
                   }
               }
               if (ptNum+2 == pts.length) {
                   // throw out oldest point
                   for (int j = 1;j < ptNum; j++) {
                       pts[j-1] = pts[j];
                   }
                   --ptNum;
               } else {
                   ptNum++;
               }
           }
           g.drawImage(bimg, 0, 0, this);
       }
       public void start() {
           thread = new Thread(this);
           thread.setPriority(Thread.MIN_PRIORITY);
           thread.setName("MemoryMonitor");
           thread.start();
       }
       public synchronized void stop() {
           thread = null;
           notify();
       }
       public void run() {           Thread me = Thread.currentThread();           while (thread == me && !isShowing() || getSize().width == 0) {
               try {
                   thread.sleep(500);
               } catch (InterruptedException e) { return; }
           }

           while (thread == me && isShowing()) {
               Dimension d = getSize();
               if (d.width != w || d.height != h) {
                   w = d.width;
                   h = d.height;
                   bimg = (BufferedImage) createImage(w, h);
                   big = bimg.createGraphics();
                   big.setFont(font);
                   FontMetrics fm = big.getFontMetrics(font);
                   ascent = (int) fm.getAscent();
                   descent = (int) fm.getDescent();
               }
               repaint();
               try {
                   thread.sleep(sleepAmount);
               } catch (InterruptedException e) { break; }
               if (MemoryMonitor.dateStampCB.isSelected()) {
                    System.out.println(new Date().toString() + " " + usedStr);
               }
           }
           thread = null;
       }
   }
   public static void main(String s[]) {
       final MemoryMonitor demo = new MemoryMonitor();
       WindowListener l = new WindowAdapter() {
           public void windowClosing(WindowEvent e) {System.exit(0);}
           public void windowDeiconified(WindowEvent e) { demo.surf.start(); }
           public void windowIconified(WindowEvent e) { demo.surf.stop(); }
       };
       JFrame f = new JFrame("Java2D Demo - MemoryMonitor");
       f.addWindowListener(l);
       f.getContentPane().add("Center", demo);
       f.pack();
       f.setSize(new Dimension(200,200));
       f.setVisible(true);
       demo.surf.start();
   }
}
没注解的呀，能给我个注解的吗？我刚学jdk，好多函数都不是很清楚

调试易

请教一applet技术问题,急救

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