1. When we implement the Runnable interface, we must define the method   run()   start()   init()   resume()   main()   Hint Half-n-half Clue   2. 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) & (E)   (A), (D) & (F)   (A), (B), (D), (E) & (F)   (D), (E) & (F)   Half-n-half Clue   3. Suppose that s1 and s2 are two strings. Which of the statements or expressions are valid? (A) String s3 = s1 + s2; (B) String s3 = s1 - s2; (C) s1 <= s2 (D) s1.compareTo(s2); (E) int m = s1.length();   (C), (D) & (E)   (A), (B) & (C)   (A), (D) & (E)   (A), (C) & (E)   (D) & (E)   Half-n-half Clue   4. Which of the following statements are valid array declaration? (A) int number(); (B) float average[]; (C) double[] marks; (D) counter int[];   (A) & (C)   (B) & (C)   (A)   (D)   Half-n-half Clue   5. Which of the following classes are available in the java.lang package? (A) Stack (B) Object (C) Math (D) Random (E) String (F) StringBuffer (G) Vector   (A), (B), (C), (E) & (F)   (C), (E) & (F)   (B), (C), (E) & (F)   (B), (E) & (F)   (B), (C) & (E)   Half-n-half Clue   6. Consider the following code int number[] = new int[5]; After execution of this statement, which of the following are true? (A) number[0] is undefined (B) number[5] is undefined (C) number[4] is null (D) number[2] is 0 (E) number.length() is 5   (B), (D) & (E)   (E)   (C) & (E)   (A) & (E)   Half-n-half Clue   7. Given the code String s = new String("abc"); Which of the following calls are valid? (A) s.trim() (B) s.replace('a', 'A') (C) s.substring(3) (D) s.toUppercase() (E) s.setCharAt(1,'A') (F) s.append("xyz")   (A), (B), (C) & (D)   (A), (B) & (C)   (A), (C), (D) & (E)   (C), (D) & (E)   (D) & (E)   Half-n-half Clue