Difference between Extend and Implement

Question

Hello guys, I still dont get it, i'm confuse, when to use Extend and when to use Implement . What's the big diference? Can anyone give me an idea?

Answer 1

I keep getting an error with this class which states: "Type parameter RectangleOperand is not within it's bounds"
import java.util.*;
public class RectangleOperand extends Rectangle2D.Double implements Addable<RectangleOperand> 
    public RectangleOperand (double w, double h)
       super(0.0,0.0,w,h);
public static RectangleOperand readRectangle(Scanner scan)
    double doubleValue;
    doubleValue = scan.nextDouble();
    RectangleOperand rectangle;
    return rectangle = new RectangleOperand(w,h);
public boolean equalTo(RectangleOperand opnd2)
     boolean equal = true;
     if(this.width == opnd2.width && this.height == opnd2.height)
         equal = true;  
     else
         equal = false;
     return equal;
public RectangleOperand plus(RectangleOperand opnd2)
     double newWidth, newHeight, width, height;
     newWidth =  (this.width)  + (opnd2.width);
     newHeight = (this.height) + (opnd2.height);
     RectangleOperand rectanglePlus = new RectangleOperand(newWidth,newHeight);
     return rectanglePlus;
}