OBJECTS AND CLASSES - Introduction to Java Programming - page 308

1 public class ShowErrors {
2 public void method1() {
3 Circle c;
4 System.out.println( "What is radius "
5 + c.getRadius());
6 c = new Circle();
7 }
8 }

1 public class ShowErrors {
2 public static void main(String[] args) {
3 C c = new C( 5.0 );
4 System.out.println(c.value);
5 }
6 }
7
8 class C {

9

int value = 2 ;

10 }

(c)

(d)

8.12

What is wrong in the following code?

1 class Test {
2 public static void main(String[] args) {
3 A a = new A();
4 a.print();
5 }
6 }
7
8 class A {
9 String s;
10
11 A(String newS) {
12 s = newS;
13 }
14
15 public void print() {
16 System.out.print(s);
17 }
18 }

8.13

What is the printout of the following code?

public class A {
private boolean x;

public static void main(String[] args) {
A a = new A();
System.out.println(a.x);

}

}

8.6 Using Classes from the Java Library
The Java API contains a rich set of classes for developing Java programs.

Key
Point

Listing 8.1 defined the SimpleCircle class and created objects from the class. You will fre-
quently use the classes in the Java library to develop programs. This section gives some exam-
ples of the classes in the Java library.

8.6.1 The Date Class
In Listing 2.6, ShowCurrentTime.java, you learned how to obtain the current time using
System.currentTimeMillis() . You used the division and remainder operators to extract