Java Reference
In-Depth Information
Example 8.1.5-1. Illegal Superinterfaces
class Redundant implements java.lang.Cloneable, Cloneable {
int x;
}
This program results in a compile-time error because the names
java.lang.Cloneable
and
Cloneable
refer to the same interface.
An interface type
I
is a superinterface of class type
C
if any of the following is true:
•
I
is a direct superinterface of
C
.
•
C
has some direct superinterface
J
for which
I
is a superinterface, using the defini-
tion of “superinterface of an interface” given in §
9.1.3
.
•
I
is a superinterface of the direct superclass of
C
.
A class can have a superinterface in more than one way.
A class is said to
implement
all its superinterfaces.
Example 8.1.5-2. Superinterfaces
interface Colorable {
void setColor(int color);
int getColor();
}
enum Finish { MATTE, GLOSSY }
interface Paintable extends Colorable {
void setFinish(Finish finish);
Finish getFinish();
}
class Point { int x, y; }
class ColoredPoint extends Point implements Colorable {
int color;
public void setColor(int color) { this.color = color; }
public int getColor() { return color; }
}
class PaintedPoint extends ColoredPoint implements Paintable {
Finish finish;
public void setFinish(Finish finish) {
this.finish = finish;
}
