Translate ADT into java interface example 3

Problem:

Translate this ADT into a Java interface:
ADT: Circle
area(): Real
center(): Point
circumference(): Real
contains(Point): Boolean
equals(Circle): Boolean
radius(): Real
toString(): String

Output:

None

Solution:

public interface Circle {
 public double area();
 public Point center();
 public double circumference();
 public boolean contains(Point point);
 public boolean equals(Object object);
 public double radius();
 public String toString();
}