添加 'w5/shape.java'

w5/shape.java

@@ -0,0 +1,29 @@
+class Shape {
+    public void draw() {}
+}
+
+class Circle extends Shape {
+    public void draw() {
+        System.out.println("Drawing a circle");
+    }
+}
+
+class Rectangle extends Shape {
+    public void draw() {
+        System.out.println("Drawing a rectangle");
+    }
+}
+
+class ShapeTest {
+    public static void drawShape(Shape shape) {
+        shape.draw();
+    }
+    
+    public static void main(String[] args) {
+        Circle circle = new Circle();
+        Rectangle rectangle = new Rectangle();
+        
+        drawShape(circle);
+        drawShape(rectangle);
+    }
+}