super, super() 추가

src/kr/co/swh/lecture/java/scene3/ChildClass.java

 	ChildClass(String date) {
 		super(date);
 	}
+	void view() {
+		super.view();
+	}
 }

src/kr/co/swh/lecture/java/scene3/ExtendsDemo.java

 public class ExtendsDemo {
 	public static void main(String[] args) { 
 		ChildClass child = new ChildClass("2019. 3. 12");
-		System.out.println(child.url);
+		System.out.println(child.date);
+		child.view();
 	}
 }

src/kr/co/swh/lecture/java/scene3/ParentClass.java

 		url = "https://swhacademy.ga";
 		this.date = date;
 	}
+	void view() {
+		System.out.println(url);
+	}
 }