Java making an arraylist of class and calling a method of that class

Question

So far I'm trying to make an ArrayList of objects that share the same method which I want to call in order of the ArrayList.

So far the code is like this

public class Shape extends Application {
   public void do(GraphicsContext canvas, int size, Color color){
     ;
   } 
}


public class Triangle extends Shape {
   @Override
   public void do(GraphicsContext canvas, int size, Color color){
      canvas.setFill(Color.WHITE);
      double[] xs = {60,80.0,50.0};
      double[] ys = {60,120.0,50.0};
      canvas.fillPolygon(xs,ys,3);
   }
}

And the main Class which launches automatically goes like this

public class Main {
    public void drawForegroundContent(GraphicContext canvas){
       ArrayList<Shape> shpes = new ArrayList<Shape>();
       Triangle t = new Triangle();
       shapes.add(t);
       shapes.add(t);

       for (Shape k : shapes){
          k.do(canvas,CoreColor.BLACK, 80);
       }
    }
}

However the error is <identifier> expected k.do(canvas, CoreColor.BLACK, 80)

Furthermore the it complains similarly on identifier on void do of Shape-class. What exactly is wrong in this code?

Answer 1

According to the docs, do is a keyword (As in the context of a do-while loop). You need to name your method something else. As the JLS say in regard to keywords:

50 character sequences, formed from ASCII letters, are reserved for use as keywords and cannot be used as identifiers

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Also side note you have the arguments out of order when you call the method. You are passing GraphicContext, Color, int, when the method accepts GraphicContext, int, Color.