import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.Graphics;
import java.lang.Math;
import java.applet.Applet;
import javax.swing.event.*;
import javax.swing.event.*;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
public class Maint extends JApplet implements

Runnable,ActionListener,MouseListener,MouseMotionLi

stener
{
/* Declaring the variables.*/
JPanel panel;
JPanel textAreaPanel;
Point dot[] = new Point[1000];
Point start, end;
int dots = 0;

JTextArea drawTextArea;
JScrollPane drawScrollPane;
JLabel line, color, paint,kid,cil;
JButton circle, rect, poly, ellipse;
JComboBox cbLine, cbFill;
GridBagLayout g;
GridBagConstraints gbc;
boolean mouseUp = false;
boolean Circle = false;
boolean Rectangle = false;
boolean Polygon = false;
boolean Ellipse = false;
Thread datimeThread;
Date date;
GregorianCalendar calendar;
String strDate, strTime, strStatus;
public void init()
{
g=new GridBagLayout();
gbc=new GridBagConstraints();
panel= (JPanel)getContentPane();
panel.setLayout(g);
paint = new JLabel("My Paint Application");
gbc.anchor= GridBagConstraints.NORTH;
gbc.gridx =2;
gbc.gridy = 0;
g.setConstraints(paint,gbc);
panel.add(paint);
rect = new JButton("Rectangle");
gbc.ipadx = 2;
gbc.ipady = 2;
gbc.gridy = 1;
gbc.gridx = 1;
g.setConstraints(rect,gbc);
panel.add(rect);
circle = new JButton("Circle");
gbc.ipadx = 2;
gbc.ipady = 2;
gbc.gridy = 1;
gbc.gridx = 2;
g.setConstraints(circle,gbc);
panel.add(circle);
poly = new JButton("Polygon");
gbc.ipadx = 2;
gbc.ipady = 2;
gbc.gridy = 1;
gbc.gridx = 3;
g.setConstraints(poly,gbc);
panel.add(poly);
ellipse = new JButton("Ellipse");
gbc.ipadx = 2;
gbc.ipady = 2;
gbc.gridy = 1;
gbc.gridx = 4;
g.setConstraints(ellipse,gbc);
panel.add(ellipse);
line = new JLabel("select line color");
gbc.ipadx = 4;
gbc.ipady = 4;
gbc.gridy = 2;
gbc.gridx = 1;
g.setConstraints(line,gbc);
panel.add(line);
kid = new JLabel("");
gbc.ipadx = 4;
gbc.ipady = 4;
gbc.gridy = 2;
gbc.gridx = 2;
g.setConstraints(kid,gbc);
panel.add(kid);
color = new JLabel("select Fill color");
gbc.ipadx = 4;
gbc.ipady = 4;
gbc.gridy = 2;
gbc.gridx = 3;
g.setConstraints(color,gbc);
panel.add(color);
String Line[]={"choose

thecolor","Red","Yellow","Green","Blue","Cyan","Man

geta","Orange"};
cbLine = new JComboBox(Line);
gbc.fill=GridBagConstraints.BOTH;
gbc.insets=new Insets(10,0,0,30);
gbc.ipadx = 4;
gbc.ipady = 4;
gbc.gridy = 3;
gbc.gridx = 1;
g.setConstraints(cbLine,gbc);
panel.add(cbLine);
cil = new JLabel("");
gbc.ipadx = 4;
gbc.ipady = 4;
gbc.gridy = 3;
gbc.gridx = 2;
g.setConstraints(cil,gbc);
panel.add(cil);
String Fill[]={"choose the

color","Red","Yellow","Green","Blue","Cyan","Manget

a","Orange"};
cbFill = new JComboBox(Fill);
gbc.fill=GridBagConstraints.BOTH;
gbc.insets=new Insets(10,0,0,30);
gbc.ipadx = 4;
gbc.ipady = 4;
gbc.gridy = 3;
gbc.gridx = 3;
g.setConstraints(cbFill,gbc);
panel.add(cbFill);
Color c =new Color(250,100,100);
Container contentpane= getContentPane();
textAreaPanel = new JPanel(new

GridLayout(2,1,5,5));
drawTextArea = new JTextArea();
drawScrollPane = new JScrollPane(drawTextArea);
textAreaPanel.add(drawScrollPane);
contentpane.setLayout(new BorderLayout());
contentpane.add(textAreaPanel,BorderLayout.CENTER);
circle.addActionListener(this);
rect.addActionListener(this);
poly.addActionListener(this);
ellipse.addActionListener(this);
addMouseListener(this);
addMouseMotionListener(this);
dateTime();
}
public void dateTime()
{
datimeThread=new Thread(this);
datimeThread.start();
}
public void run()
{
while(datimeThread !=null)
{
display();
try
{
datimeThread.sleep(1000);
}
catch(InterruptedException e)
{
showStatus("Thread interrupted");
}
}
}
public void display()
{
date =new Date();
calendar =new GregorianCalendar();
calendar.setTime(date);
strTime =

calendar.get(Calendar.HOUR)+":"+calendar.get(Calend

ar.MINUTE)+":"+calendar.get(Calendar.SECOND);
strDate=

(calendar.get(Calendar.MONTH)+1)+"/"+calendar.get(C

alendar.DATE)+"/"+calendar.get(Calendar.YEAR);
strStatus=strTime+" "+strDate;
showStatus(strStatus);
setSize(700,500);
setVisible(true);
}
public void mousePressed(MouseEvent e)
{
mouseUp = false;
start = new Point(e.getX(), e.getY());
}
public void mouseReleased(MouseEvent e)
{
if(Circle){
end = new Point(e.getX(), e.getY());
} else {
end = new Point(Math.max(e.getX(), start.x),
Math.max(e.getY(), start.y));
start = new Point(Math.min(e.getX(), start.x),
Math.min(e.getY(), start.y));
}
mouseUp = true;
repaint();
}
public void mouseDragged(MouseEvent e)
{
if(Ellipse){
dot[dots] = new Point(e.getX(), e.getY());
dots++;
repaint();
}
}
public void mouseClicked(MouseEvent e){}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mouseMoved(MouseEvent e){}
public void paint (Graphics g)
{
if (mouseUp) {
int width = end.x - start.x;
int height = end.y - start.y;
if(Circle){
g.drawOval(start.x, start.y, width, height);
}
else if(Rectangle){
g.drawRect(start.x, start.y, width, height);
}
else if(Polygon){
g.drawRoundRect(start.x, start.y, width, height,

10, 10);
}
else if(Ellipse){
for(int loop_index = 0; loop_index < dots - 1;
loop_index++){
g.drawLine(dot[loop_index].x, dot[loop_index].y,
dot[loop_index + 1].x, dot[loop_index + 1].y);
}
}
}
}
public void actionPerformed(ActionEvent e)
{
setFlagsFalse();
if(e.getSource() == poly)Polygon = true;
if(e.getSource() == circle)Circle = true;
if(e.getSource() == rect)Rectangle = true;
if(e.getSource() == ellipse)Ellipse = true;
}
void setFlagsFalse()
{
Polygon = false;
Circle = false;
Rectangle = false;
Ellipse = false;
}
}


Firstly,before add listener to it ,the JTextarea show but please, assist me on how to let the buttons, labels and combobox be in NORTH and JTextarea in SOUTH and show clearly.
secondly, after add listener, it does not shown at all except time/date

It doesn't show because you reset the layout on the content pane before you add the text area panel. You can't just change the layout on the container like that midway through adding components. If you need to have separately laid out sections, create panels for those sections and place your components on those panels in whatever layout you need, then add those panels in an appropriate layout to the content pane.

Also, please use code tags when posting code. It is difficult to read the long unformatted mess that results when you put the code straight into the post.