Getting Mouse Click Method To Change Previous Object Properties?

I am having trouble with a mouse click method. In short I have a hexagon grid, and every time I want to click on one particular hexagon I want the color of the hexagon to change to blue(by default the color is grey). This part works, but when I go to click on another hexagon I want the color of the previous hexagon to change back to grey while at the same time changing the color of the current hexagon clicked to blue. So in other words, I only want one hexagon blue at a time. How might I do this?

I have a hexagon class for one particular hexagon, and a hexmap class for multiple hexagons. I know I should probably be handling mouse clicks in the hexmap since it deals with the whole thing. But I cannot say something like hexagon.setColor within a mouselistener in that class(it gives me a lot of issues). Here is some of my code :

public class Hexagons()
public Hexagons(HexMap theMap, int mapRow, int mapCol, int width, int height) {
this.map = theMap;
this.row = mapRow;
this.col = mapCol;
this.width = width;
this.height = height;

[Code] ....