Type Information(Thinking in Java)
Shapes
1 import java.util.*;
2
3 abstract class Shape
4 {
5 void draw()
6 {
7 System.out.println(this + ".draw()");
8 }
9 abstract public String toString();
10 }
11
12 class Circle extends Shape
13 {
14 public String toString()
15 {
16 return "Circle";
17 }
18 }
19
20 class Square extends Shape
21 {
22 public String toString()
23 {
24 return "Square";
25 }
26 }
27
28 class Triangle extends Shape
29 {
30 public String toString()
31 {
32 return "Triangle";
33 }
34 }
35
36 public class Shapes
37 {
38 public static void main(String[] args)
39 {
40 List<Shape> shapeList = Arrays.asList(new Circle(), new Square(), new Triangle());
41 for(Shape shape : shapeList)
42 {
43 shape.draw();
44 }
45 }
46 }
47
2
3 abstract class Shape
4 {
5 void draw()
6 {
7 System.out.println(this + ".draw()");
8 }
9 abstract public String toString();
10 }
11
12 class Circle extends Shape
13 {
14 public String toString()
15 {
16 return "Circle";
17 }
18 }
19
20 class Square extends Shape
21 {
22 public String toString()
23 {
24 return "Square";
25 }
26 }
27
28 class Triangle extends Shape
29 {
30 public String toString()
31 {
32 return "Triangle";
33 }
34 }
35
36 public class Shapes
37 {
38 public static void main(String[] args)
39 {
40 List<Shape> shapeList = Arrays.asList(new Circle(), new Square(), new Triangle());
41 for(Shape shape : shapeList)
42 {
43 shape.draw();
44 }
45 }
46 }
47
SweetShop
1 class Candy
2 {
3 static
4 {
5 System.out.println("Loading Candy");
6 }
7 }
8
9 class Gum
10 {
11 static
12 {
13 System.out.println("Loading Gum");
14 }
15 }
16
17 class Cookie
18 {
19 static
20 {
21 System.out.println("Loading Cookie");
22 }
23 }
24
25 public class SweetShop
26 {
27 public static void main(String[] args)
28 {
29 System.out.println("inside main");
30 new Candy();
31 System.out.println("After creating Candy");
32 try
33 {
34 Class.forName("Gum");
35 }
36 catch(ClassNotFoundException e)
37 {
38 System.out.println("Couldn't find Gum");
39 }
40 System.out.println("After Class.forName(\"Gum\")");
41 new Cookie();
42 System.out.println("After creating Cookie");
43 }
44 }
2 {
3 static
4 {
5 System.out.println("Loading Candy");
6 }
7 }
8
9 class Gum
10 {
11 static
12 {
13 System.out.println("Loading Gum");
14 }
15 }
16
17 class Cookie
18 {
19 static
20 {
21 System.out.println("Loading Cookie");
22 }
23 }
24
25 public class SweetShop
26 {
27 public static void main(String[] args)
28 {
29 System.out.println("inside main");
30 new Candy();
31 System.out.println("After creating Candy");
32 try
33 {
34 Class.forName("Gum");
35 }
36 catch(ClassNotFoundException e)
37 {
38 System.out.println("Couldn't find Gum");
39 }
40 System.out.println("After Class.forName(\"Gum\")");
41 new Cookie();
42 System.out.println("After creating Cookie");
43 }
44 }
ToyTest 1 interface HasBatteries{}
2 interface Waterproof{}
3 interface Shoots{}
4
5 class Toy
6 {
7 Toy(){}
8 Toy(int i){}
9 }
10
11 class FancyToy extends Toy implements HasBatteries, Waterproof, Shoots
12 {
13 FancyToy() { super(1); }
14 }
15
16 public class ToyTest {
17 static void printInfo(Class cc)
18 {
19 System.out.println("Class name: " + cc.getName() +
20 " is interface? [" + cc.isInterface() + "]");
21 System.out.println("Simple name: " + cc.getSimpleName());
22 System.out.println("Canonical name: " + cc.getCanonicalName());
23 }
24
25 public static void main(String[] args)
26 {
27 Class c = null;
28 try
29 {
30 c = Class.forName("FancyToy");
31 }
32 catch(ClassNotFoundException e)
33 {
34 System.out.println("Cannot find FancyToy");
35 System.exit(1);
36 }
37 printInfo(c);
38 for(Class face : c.getInterfaces())
39 {
40 printInfo(face);
41 }
42 Class up = c.getSuperclass();
43 Object obj = null;
44 try
45 {
46 obj = up.newInstance();
47 }
48 catch(InstantiationException e)
49 {
50 System.out.println("Cannot instantiate");
51 }
52 catch(IllegalAccessException e)
53 {
54 System.out.println("Cannot access");
55 System.exit(1);
56 }
57
58 printInfo(obj.getClass());
59 }
60 }
2 interface Waterproof{}
3 interface Shoots{}
4
5 class Toy
6 {
7 Toy(){}
8 Toy(int i){}
9 }
10
11 class FancyToy extends Toy implements HasBatteries, Waterproof, Shoots
12 {
13 FancyToy() { super(1); }
14 }
15
16 public class ToyTest {
17 static void printInfo(Class cc)
18 {
19 System.out.println("Class name: " + cc.getName() +
20 " is interface? [" + cc.isInterface() + "]");
21 System.out.println("Simple name: " + cc.getSimpleName());
22 System.out.println("Canonical name: " + cc.getCanonicalName());
23 }
24
25 public static void main(String[] args)
26 {
27 Class c = null;
28 try
29 {
30 c = Class.forName("FancyToy");
31 }
32 catch(ClassNotFoundException e)
33 {
34 System.out.println("Cannot find FancyToy");
35 System.exit(1);
36 }
37 printInfo(c);
38 for(Class face : c.getInterfaces())
39 {
40 printInfo(face);
41 }
42 Class up = c.getSuperclass();
43 Object obj = null;
44 try
45 {
46 obj = up.newInstance();
47 }
48 catch(InstantiationException e)
49 {
50 System.out.println("Cannot instantiate");
51 }
52 catch(IllegalAccessException e)
53 {
54 System.out.println("Cannot access");
55 System.exit(1);
56 }
57
58 printInfo(obj.getClass());
59 }
60 }
