specializedpoint.java

用java实现继承实例

public class SpecializedPoint extends Point {
 SpecializedPoint(){
 	super();
}
SpecializedPoint(double x ,double y){
 	super(x,y);
}
public void setX(double x){
	if (x<0)
	throw new UnsupportedOperationException("x must be greater than 0");
	}

}