I have a question, been working on a Java game and I am wondering what eclipse means when it gives me the warning:

Box.class:
Java Code:
package main;public class Box { public final int x1
; public final int y1
; public final int x2
; public final int y2
; public Box(int x1,
int y1,
int x2,
int y2
) { this.
x1 = x1
; this.
x2 = x2
; this.
y1 = y1
; this.
y2 = y2
; } public static boolean collision
(Box box1,
Box box2
) { return !((box1.
y2 < box2.
y1) || (box1.
y1 > box2.
y2) || (box1.
x1 > box2.
x2) || (box1.
x2 < box2.
x1) ); } public boolean collision
(Box box
) { return this.
collision(this, box
); }}
this line:
java Code:
return this.collision(this, box);