It looks I don't understand this question, as below is the constructor of RectangleShape:
public RectangleShape(double minX, double maxY, double maxX, double minY)
The UpperLeft corner: minX, maxY
The UpperRight corner: maxX, maxY
The LowerLeft corner: minX, minY
The LowerRight corner: maxX, minY
So your four points had been used for create the RectangleShape.