Given the code fragment:

Which statement can be inserted into line n1 to print 1,2; 1,10; 2,20;?

Given:
class UserException extends Exception { }
class AgeOutOfLimitException extends UserException { }
and the code fragment:
class App {
public void doRegister(String name, int age)
throws UserException, AgeOutOfLimitException {
if (name.length () < 6) {
throw new UserException ();
} else if (age >= 60) {
throw new AgeOutOfLimitException ();
} else {
System.out.println("User is registered.");
}
}
public static void main(String[ ] args) throws UserException {
App t = new App ();
t.doRegister("Mathew", 60);
}
}
What is the result?

Given the code fragment:

What is the result?

Given:
Book.java:
public class Book {
private String read(String bname) { return "Read" + bname }
}
EBook.java:
public class EBook extends Book {
public class String read (String url) { return "View" + url }
}
Test.java:
public class Test {
public static void main (String[] args) {
Book b1 = new Book();
b1.read("Java Programing");
Book b2 = new EBook();
b2.read("http://ebook.com/ebook");
}
}
What is the result?

You want to create a singleton class by using the Singleton design pattern.
Which two statements enforce the singleton nature of the design? (Choose two.)