Selected Questions from by Nageshwara Rao

Transcription

1 Selected Questions from by Nageshwara Rao Swaminathan J Amrita University swaminathanj@am.amrita.edu November 24, 2016 Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

2 Question 1 1. What makes Java platform-independent? a) JVM b) Java syntax c) Java API d) bytecode Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

3 Question 2 2. Which occupies more number of bits of memory? a) double b) long c) occupies same d) depends on the value Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

4 Question 3 3. The object is created with new keyword a) at compile-time b) at run-time c) depends on the code d ) none Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

5 Question 4 4. Integer.parseInt() is used to convert an integer to string. a) True b) False Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

6 Question 5 5. One way of implementing data protection is declaring instance variables as private and methods as public. a) True b) False Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

7 Question 6 6. What is the output of the following code? int x = 99, y = 100 ; System.out.println( x / y ) ; a) does not compile b) 0 c) d) none Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

8 Question 7 7. Below code raises compilation error since arithmetic operations are not possible on characters. char k = A ; System.out.println( k * k ) ; a) True b) False Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

9 Question 8 8. The output of the 3 println statements is same. System.out.println(25/4.0); System.out.println(25.0/4.0); System.out.println(25.0/4); a) True b) False Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

10 Question 9 9. What is the output of the program? class Num { Num(double x ) { System.out.println(x); } class Numbers extends Num { public static void main(string[] args) { Num num = new Num(2) ; } } a) 0 b) 2.0 c) 2 d) Type mismatch error Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

11 Question final methods cannot be overridden but overloaded. a) True b) False Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

12 Question The implicit return type of a constructor is a) void b) boolean c) null d) depends upon the called method e) a class object in which it is defined Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

13 Question What is the output of the following program? class Numbers { public int display(int x, int y) { return ( sum of x and y is + x+y); } public static void main(string args[]) { Numbers num = new Numbers(); System.out.println(num.display(4,5)); } } a) sum of x and y is 9 b) sum of x and y is 45 c) does not compile d) none Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

14 Question What is the output of the following program? class staticmethods { static void display() { System.out.println( display ); } static { System.out.println( only static no method ); } public static void main(string s[]) { display(); } } Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

15 Question The below code creates Room object and prints public class Room { public static void main(string args[]) { int height=10, width=10, length=20; System.out.println( Volume is + (width*height*length)); } } a) true b) false Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

16 Question All classes in a source file should contain main method. a) true b) false Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

17 Question The main method should be static for the reason a) it can be accessed easily by the class loader. b) it can be accessed by every method or variable without any hindrance. c) it can be executed without creating any instance of the class. d) none Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

18 Question Arrays are a) objects b) object references c) primitive data types d) none Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

19 Question All the below three statements are invalid. char[] c = new char(); char[] c = new char(4); char[] c = new char[]; a) True b) False Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

20 Question Both ways of declaration are correct. int[] intarray1 = new int[] { 10, 20 }; int[] intarray2 = { 10, 20 }; a) True b) False Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

21 Question The output of the above fraction of code is String s1 = new String( Hello ); String s2 = new String( Hellow ); System.out.println(s1 = s2); a) Hello b) Hellow c) does not compile d) throws an exception e) none Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

22 Question The below code prints bcd. String str1 = abcde ; System.out.println(str1.substring(1, 3)); a) True b) False Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

23 Question What output does this fragment code displays? String str = ONE ONE ; System.out.println(str.indexOf( O )); a) 0 b) 1 c) 5 d) 6 e) 0 and 5 f) error message g) none Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

24 Question What is the output? StringBuffer sb = new StringBuffer( SCJP Exam ); sb.setlength(0); System.out.println(sb); a) SCJP Exam b) 0 c) 1 d) no output e) exception Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

25 Question The output of the below fragment of code is String str = Hello ; str.insert(2, k ); System.out.println(str); a) Hello b) Helklo c) Hekllo d) none Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1

26 Question Garbage collector invoked using System.gc()? a) True b) False Swaminathan J (Amrita University) way2java.com (Nageshwara Rao) November 24, / 1