This is a mini-paint program which uses class Point. It is very basic and allows a line to be drawn, then altered by its size and color. The issue that I am having is when I change color or size, all of the previous lines change with it?

import java.awt.*;
import java.awt.event.*;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;
import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;

public class Painter extends JFrame 
   private int pointCount = 0;
   private int size1 = 4;
   private int size2 = 4;
   private JRadioButton thinButton;
   private JRadioButton mediumButton;
   private JRadioButton thickButton;
   private JButton changeColorButton;
   private Color color = Color.BLACK;
   private Container container;

   // array of 1000 java.awt.Point references
   private Point points[] = new Point[ 1000 ];  

   // set up GUI and register mouse event handler
   public Painter()
      super( "A simple paint program" );
      class MouseDraggedPoint extends MouseMotionAdapter

          // store drag coordinates and repaint
         public void mouseDragged( MouseEvent event )
               if ( pointCount < points.length )
                  points[ pointCount ] = event.getPoint();
      MouseDraggedPoint draggedPoint  = new MouseDraggedPoin();
      setSize( 800, 300 );  
      setVisible( true );  
      JPanel buttonPanel = new JPanel();
      ButtonGroup group = new ButtonGroup();
      thinButton = addRadioButton(buttonPanel, group, "Thin", true);
      mediumButton = addRadioButton(buttonPanel,group, "Medium", false);
      thickButton = addRadioButton(buttonPanel, group, "Thick", false);

      thinButton.addItemListener(new SelectItemListener());
      mediumButton.addItemListener(new SelectItemListener());
      thickButton.addItemListener(new SelectItemListener());

      // set up changeColorButton and register its event handler
      changeColorButton = new JButton( "Change Color" );
      ActionListener listener = new ColorListener(); 
      getContentPane().setLayout( new FlowLayout() );
      getContentPane().add( new JLabel( "Drag the mouse to draw"));


  public JRadioButton addRadioButton(JPanel buttonPanel, ButtonGroup g,
      String buttonName, boolean v) {
    JRadioButton button = new JRadioButton(buttonName, v);

    return button;

  public JButton addJButton(JPanel buttonPanel, String buttonName)
      JButton button = new JButton(buttonName);
  class SelectItemListener implements ItemListener
        public void itemStateChanged(ItemEvent e)
                Object source = e.getSource();
                if (source == thinButton)
                size1 = 2;
                else if (source == mediumButton)
                size1 = 12;
                else if (source == thickButton)
                size1 = 24;


      * display JColorChooser when user clicks button
     class ColorListener implements ActionListener
            public void actionPerformed( ActionEvent event )
               color = JColorChooser.showDialog( 
                        Painter.this, "Choose a color", color );

        } // end ColorListener class 
    // end Painter constructor

   /** draw oval in a 4-by-4 bounding box at specified location on window */
   public void paint( Graphics g )
      super.paint( g ); // clears drawing area

      for ( int i = 0; i < points.length && points[ i ] != null; i++ )
         g.fillOval( points[ i ].x, points[ i ].y, size1, size2 );


   public static void main( String args[] )
      Painter application = new Painter();
      application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

} // end class Painter

It is more like logic problem than technology problem. Note that paint method is called everytime there is change in the Graphics. It is beyond your code's control. Which means every time something happens (like re-size / hide-unhide), Graphics gets refreshed, calling paint method.
Now you are drawing (fillOval) all the time, using the same size1, size2 variables. What you need is another class (structure) to save all the info that is related to a specific part of drawing, like points, line thickness, color etc. And your main drawing will be collection (like an Arraylist) of these structures. Your paint will use these instances paint.
Hope this gives you some direction to think.