[Java] Determine 2 points from player position

We know the player position and rotation. We have to create a box in front of the player, facing the same direction as the player. We know the width and length of the box. I need help to figure out the math to calculate the bottom left Point and the Top right Point of the box area in front of the player. We use the player position as origin, and the player Y rotation to make sure the box is facing the player. An image explaining my issue visually : [login to view URL]