LWJGL Antialiased lines

Hi, I am making a minimap for my game. (See top right corner of below image)

Everything is perfect, except for the jagged outline. I draw lines around the edges of the map, but they aren’t smooth.

I’ve played around with the following settings:
GL11.glEnable(GL11.GL_LINE_SMOOTH);
GL11.glHint(GL11.GL_PERSPECTIVE_CORRECTION_HINT, GL11.GL_NICEST);

and they just make the lines look worse. Searching on google, I came across something called multisampling, I’m not sure if this is what I want though.

Note, this is rendering to a seperate texture. I don’t want full-scene antialiasing, just for the lines that make up the background of the minimap.

Can anyone help me?
Thanks,
Roland