How is java animated with string?

I am learning to use Java Swing and have made a simple animation that makes a small shape bounce around the predetermined borders of a panel. The program works well, but I am looking for feedback in terms of quality and any improvements or alternative methods that could be used in such an application.

import javax.swing.*;

import java.awt.*;

final public class Tester {

JFrame frame;

    DrawPanel drawPanel;

   private int oneX = 7;

    private int oneY = 7;  

boolean up = false;

    boolean down = true;

    boolean left = false;

    boolean right = true;

    public static void main(String[] args) {
        new Tester().go();
    }
    private void go() {
        frame = new JFrame("Test");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        drawPanel = new DrawPanel();
        frame.getContentPane().add(BorderLayout.CENTER, drawPanel);
        frame.setVisible(true);
        frame.setResizable(false);
        frame.setSize(300, 300);
        frame.setLocation(375, 55);
        moveIt();
    }
    class DrawPanel extends JPanel {
        public void paintComponent(Graphics g) {
            g.setColor(Color.BLUE);
            g.fillRect(0, 0, this.getWidth(), this.getHeight());
            g.setColor(Color.RED);
            g.fillRect(3, 3, this.getWidth()-6, this.getHeight()-6);
            g.setColor(Color.WHITE);
            g.fillRect(6, 6, this.getWidth()-12, this.getHeight()-12);
            g.setColor(Color.BLACK);
            g.fillRect(oneX, oneY, 6, 6);
        }
    }
    private void moveIt() {
        while(true){
            if(oneX >= 283){
                right = false;
                left = true;
            }
            if(oneX <= 7){
                right = true;
                left = false;
            }
            if(oneY >= 259){
                up = true;
                down = false;
            }
            if(oneY <= 7){
                up = false;
                down = true;
            }
            if(up){
                oneY--;
            }
            if(down){
                oneY++;
            }
            if(left){
                oneX--;
            }
            if(right){
                oneX++;
            }
            try{
                Thread.sleep(10);
            } catch (Exception exc){}
            frame.repaint();
        }
    }
}