polar co-ordinates : Java Glossary

Polar	Cartesian	Java Drawing

You can convert polar co-ordinates to Cartesian x,y co-ordinates with:

// polar to Cartesian
double x = Math.cos( angleInRadians ) * radius;
double y = Math.sin( angleInRadians ) * radius;

// Cartesian to polar.
double radius = Math.sqrt( x * x + y * y );
double angleInRadians = Math.acos( x / radius );