1. 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   (E)   (C) & (E)   (B), (D) & (E)   (A) & (E)   Hint Half-n-half Clue   2. Which of the following statements are valid array declaration? (A) int number(); (B) float average[]; (C) double[] marks; (D) counter int[];   (D)   (A)   (A) & (C)   (B) & (C)   Half-n-half Clue   3. 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)   (D) & (E)   (C), (D) & (E)   Half-n-half Clue   4. 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   (B), (C) & (E)   (A), (B), (C), (E) & (F)   (B), (C), (E) & (F)   (B), (E) & (F)   (C), (E) & (F)   Half-n-half Clue   5. 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();   (D) & (E)   (A), (B) & (C)   (A), (D) & (E)   (C), (D) & (E)   (A), (C) & (E)   Half-n-half Clue   6. The methods wait() and notify() are defined in   java.lang.Thread   java.lang.String   java.lang.Object   java.lang.Runnable   java.lang.ThreadGroup   Half-n-half Clue   7. Which of the following are the wrapper classes? (A) Random (B) Byte (C) Vector (D) Integer (E) Short (F) Double (G) String   (B), (D) & (F)   (B), (D), (E) & (F)   (A), (B), (D), (E) & (F)   (B), (D) & (E)   (D), (E) & (F)   Half-n-half Clue