import java.awt.*;        // Defines basic classes for GUI programming.
     import java.awt.event.*;  // Defines classes for working with events.
     import java.applet.*;     // Defines the applet class.
 


/*<applet code="ColoredHelloWorldApplet" width=300 height=400>
</applet>
*/
     public class ColoredHelloWorldApplet
                       extends Applet implements ActionListener {
 
           // Defines a subclass of Applet.  The "implements ActionListener"
           // part says that objects of type ColoredHelloApplet are
           // capable of listening for ActionEvents.  This is necessary
           // if the applet is to respond to events from the button.
 
        Font textFont;    // The font in which the message is displayed.
                          // A font object represent a certain size and
                          // style of text drawn on the screen.
        TextField T1;
        TextField T2;
        TextField T3;
        int redColor, greenColor, blueColor;
        String as, ag, ab;
        Button bttn;
        public void init() {
 
               // This routine is called by the system to initialize 
               // the applet.  It sets up the font and initial colors
               // the applet.  It adds a button to the applet for 
               // changing the message color.
 
            setBackground(Color.lightGray);
                  // The applet is filled with the background color before
                  // the paint method is called.  The button and the message
                  // in this applet will appear on a light gray background.
 
            redColor=0;
            greenColor=0;
            blueColor=0;
 
 
            textFont = new Font("Serif",Font.BOLD,24);
                  // Create a font object representing a big, bold font.
 
     /*
     		TextField T1=new TextField("",12);
     		TextField T2=new TextField("",12);
     		TextField T3=new TextField("",12);
     		*/
 
     		T1=new TextField("",12);
     	 	T2=new TextField("",12);
     	 	T3=new TextField("",12);
 
 
     		add(T1);
     		add(T2);
     		add(T3);
            bttn = new Button("Change Color");
                  // Create a new button.  "ChangeColor" is the text
                  // displayed on the button.
 
            bttn.addActionListener(this);  
                  // Set up bttn to send an "action event" to this applet
                  // when the user clicks the button.  The parameter, this,
                  // is a name for the applet object that we are creating.
 
            add(bttn);  // Add the button to the applet, so that it 
                        // will appear on the screen.
 
        }  // end init()
 
 
        public void paint(Graphics g) {
 
              // This routine is called by the system whenever the content
              // of the applet needs to be drawn or redrawn.  It displays 
              // the message "Hello World" in the proper color and font.
 
           Color mixColor=new Color(redColor, greenColor,blueColor);
           //Color mixColor=new Color(255,255,50);
 
           //g.setColor(mixColor);
           g.setColor(mixColor);
           //g.setColor(new Color(redColor, greenColor, blueColor));
           g.setFont(textFont);       // Set the font.
 
           g.drawString("This Color changes", 20,70);    // Draw the message.
           //T1.setText("Is this function reached");
 
        }  // end paint()
 
 
        public void actionPerformed(ActionEvent evt) {
 
              // This routine is called by the system when the user clicks
              // on the button.  The response is to change the colorNum
              // which determines the color of the message, and to call
              // repaint() to see that the applet is redrawn with the
              // new color.
            // T1.setText("23");
 
            if (evt.getSource() == bttn)
            {
 
              as=T1.getText();
              ag=T2.getText();
              ab=T3.getText();
       	  	  as=as.trim();
          	  ag=ag.trim();
              ab=ab.trim();
 
           redColor= Integer.parseInt(as);
           greenColor= Integer.parseInt(ag);
           blueColor= Integer.parseInt(ab);
 
           repaint();  // Tell system that this applet needs to be redrawn
          }
        }  // end init()
 
     } // end class ColoredHelloWorldApplet

Output: