1. Which of the following statements are valid array declaration? (A) int number(); (B) float average[]; (C) double[] marks; (D) counter int[];   (A)   (D)   (B) & (C)   (A) & (C)   Hint Half-n-half Clue   2. When we implement the Runnable interface, we must define the method   run()   start()   main()   init()   resume()   Half-n-half Clue   3. Which of the following statements are true? (A) A Java monitor must either extend Thread or implement Runnable. (B) The sleep() method should be enclosed in try ... catch block. (C) The yield() method should be enclosed in try ... catch block. (D) A thread can be temporarily suspended from running by using the wait() method. (E) A suspended thread using suspend() method can be revived using the resume() method.   (A), (B), (D) & (E)   (B), (D) & (E)   (A), (B) & (D)   (C), (D) & (E)   (D) & (E)   Half-n-half Clue   4. The methods wait() and notify() are defined in   java.lang.ThreadGroup   java.lang.Runnable   java.lang.String   java.lang.Object   java.lang.Thread   Half-n-half Clue   5. Given the following code: class Base { int x = 10; } class Derived extends Base { int x = 20; } Base b = new Base(); Derived d = new Derived ( ); Base bd = new Derived(); The statement System.out.println(b.x + " " + d.x + " " + bd.x); will produce the output   20 20 10   20 10 20   10 20 10   10 20 20   Half-n-half Clue   6. Given the class definitions class Base { void display () { System.out.println("Base"); } } class Derived extends Base { void display () { System.out.println("Derived"); } } and objects Base b = new Base(); Derived d = new Derived(); Base bd = new Derived; then the print statements System.out.print(b.display() + " "); System.out.print(d.display() + " "); System.out.print(bd.display() + " "); System.out.println(); will display:   Base Derived Base   Base Derived Derived   Base Base Derived   Derived Derived Derived   Half-n-half Clue   7. Which of the following contain error? (A) int x[] = int[10]; (B) int[] y = new int[5]; (C) float d[] =   (A), (E) & (F)   (A), (D) & (F)   (A), (D) & (E)   (A), (B), (D), (E) & (F)   (D), (E) & (F)   Half-n-half Clue