CIT 594 Drawing the "Bug"
Spring 2008, David Matuszek

Here's a bit of code to draw a "Bug" facing the given angle, where angle is measured in degrees counterclockwise from East. 
/**
 * Paints a triangle to represent this Bug.
 * 
 * @param g Where to paint this Bug.
 */
public void paint(Graphics g) {
    if (color == null) return;
    g.setColor(color);
    
    int x1 = (int) (scaleX(x) + computeDeltaX(12, (int)angle));
    int x2 = (int) (scaleX(x) + computeDeltaX(6, (int)angle - 135));
    int x3 = (int) (scaleX(x) + computeDeltaX(6, (int)angle + 135));
    
    int y1 = (int) (scaleY(y) + computeDeltaY(12, (int)angle));
    int y2 = (int) (scaleY(y) + computeDeltaY(6, (int)angle - 135));
    int y3 = (int) (scaleY(y) + computeDeltaY(6, (int)angle + 135));
    g.fillPolygon(new int[] { x1, x2, x3 }, new int[] { y1, y2, y3 }, 3);
}

/**
 * Computes how much to move to add to this Bug's x-coordinate,
 * in order to displace the Bug by "distance" pixels in 
 * direction "degrees".
 * 
 * @param distance The distance to move.
 * @param degrees The direction in which to move.
 * @return The amount to be added to the x-coordinate.
 */
private static double computeDeltaX(int distance, int degrees) {
    double radians = Math.toRadians(degrees);
    return distance * Math.cos(radians);
}

/**
 * Computes how much to move to add to this Bug's y-coordinate,
 * in order to displace the Bug by "distance" pixels in 
 * direction "degrees.
 * 
 * @param distance The distance to move.
 * @param degrees The direction in which to move.
 * @return The amount to be added to the y-coordinate.
 */
private static double computeDeltaY(int distance, int degrees) {
    double radians = Math.toRadians(degrees);
    return distance * Math.sin(-radians);
}
You will have to adapt this code slightly. The methods scaleX and scaleY convert from "Bugs coordinates" (0.0 to 100.0) to the Java coordinates used in the actual JPanel (0 to panel width in pixels, 0 to panel height in pixels).