我想运行书上的这个程序要怎么做

我用的是 editplus 和 命令方式

帮我解决一下 java Ch1_7.class 不能执行的问题

Ch1_7.java

import java.awt.*;
import java.applet.*;

public class Ch1_7 extends Applet
{
    int width, height;
    Image image;

    Graphics g1;

    public void init ( )
    {
        setBackground ( Color.black );
        this.setSize ( 350, 310 );

        width = getSize ( ).width;
        height = getSize ( ).height;
        image = createImage ( width, height );
        g1 = image.getGraphics ( );
    }

    public void paint ( Graphics g )
    {
        g1.clearRect ( 0, 0, width, height );
        g1.setColor ( Color.red );
        int i, j;
        double x, y, r;

        for ( i = 0; i <= 90; i ++ )
            for ( j = 0; j <= 90; j ++ )
            {
                r = Math.PI / 45 * i * ( 1 - Math.sin ( Math.PI / 45 * j ) ) * 18;
                x = r * Math.cos ( Math.PI /45 * j ) * Math.sin ( Math.PI / 45 * i ) + width / 2;
                y = -r * Math.sin ( Math.PI /45 * j ) + height / 4;

                g1.fillOval ( ( int ) x, ( int ) y, 2, 2 );
                g1.fillRect ( ( int ) x, ( int ) y, 1, 1 );
            }
        g.drawImage ( image, 0, 0, this );
    }
}

我用的是 editplus 和 命令方式

帮我解决一下 java Ch1_7.class 不能执行的问题

Ch1_7.java

import java.awt.*;
import java.applet.*;

public class Ch1_7 extends Applet
{
    int width, height;
    Image image;

    Graphics g1;

    public void init ( )
    {
        setBackground ( Color.black );
        this.setSize ( 350, 310 );

        width = getSize ( ).width;
        height = getSize ( ).height;
        image = createImage ( width, height );
        g1 = image.getGraphics ( );
    }

    public void paint ( Graphics g )
    {
        g1.clearRect ( 0, 0, width, height );
        g1.setColor ( Color.red );
        int i, j;
        double x, y, r;

        for ( i = 0; i <= 90; i ++ )
            for ( j = 0; j <= 90; j ++ )
            {
                r = Math.PI / 45 * i * ( 1 - Math.sin ( Math.PI / 45 * j ) ) * 18;
                x = r * Math.cos ( Math.PI /45 * j ) * Math.sin ( Math.PI / 45 * i ) + width / 2;
                y = -r * Math.sin ( Math.PI /45 * j ) + height / 4;

                g1.fillOval ( ( int ) x, ( int ) y, 2, 2 );
                g1.fillRect ( ( int ) x, ( int ) y, 1, 1 );
            }
        g.drawImage ( image, 0, 0, this );
    }
}

非常感谢！！以后还会有很多问题麻烦前辈，还望不吝赐教。