Java color opacity

I have a way to determine the color based on certain values The method is as follows:

public Color color(double val) {
    double H = val * 0.3; 
    double S = 0.9; 
    double B = 0.9; 
    return Color.getHSBColor((float)H,(float)S,(float)B);
}

I also want to make the color transparent How can I do this? thank you

Solution

The simplest way is to specify R, G, B and a directly using the following constructors:

public Color(float r,float g,float b,float a).

I know you have HSB, but you can easily convert to RGB