PyramidDemo.java

// class draw pyramid sync - pass char
class PyramidDemo
{
    public static void main(String args[])
    {
        Draw d = new Draw();
        DrawStar ds = new DrawStar(d,'*');
        DrawDollar dd = new DrawDollar(d,'$');
        ds.start();
        dd.start();
    }
}
class Draw
{
    synchronized void drawPyramid(char ch)
    {
        for(int i=0;i<5;i++)
                {
                    for(int j=5-i;j>1;j--)
                    {
                        System.out.print(" ");
                    }
                    for(int j=0;j<=i;j++)
                    {
                        System.out.print(ch + " ");
                    }
                    System.out.println(" ");
        }
    }
}

class DrawStar extends Thread
{
        Draw d;
        char ch;
        DrawStar(Draw d,char ch)
        {
            this.d = d;
            this.ch = ch;
        }
        public void run()
        {
            d.drawPyramid(ch);
        }
}
class DrawDollar extends Thread
{
        Draw d;
        char ch;
        DrawDollar(Draw d,char ch)
        {
            this.d = d;
            this.ch = ch;
        }
        public void run()
        {
            d.drawPyramid(ch);
        }
}