Instruction
- Total number of questions : 20.
- Time alloted : 20 minutes.
- Each question carry 1 mark.
- No Negative marks
- DO NOT refresh the page.
- All the best :-).
1. |
What is the output of this program? class increment { public static void main(String args[]) { int g = 3; System.out.print(++g * 8); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option C Explanation: Operator ++ has more preference than *, thus g becomes 4 and when multiplied by 8 gives 32. |
2. |
What is the output of this program? class booloperators { public static void main(String args[]) { boolean var1 = true; boolean var2 = false; System.out.println((var2 & var2)); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option D Explanation: boolean ‘&’ operator always returns true or false. var1 is defined true and var2 is defined false hence their ‘&’ operator result is false. |
3. |
Which of these is incorrect string literal? |
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Your Answer: Option (Not Answered) Correct Answer: Option D Explanation: all string literals must begin and end in same line. |
4. |
What is the output of this program, if we run as “java main_arguments 1 2 3”? class main_arguments { public static void main(String [] args) { String [][] argument = new String[2][2]; int x; argument[0] = args; x = argument[0].length; for (int y = 0; y < x; y++) System.out.print(" " + argument[0][y]); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option D Explanation: In argument[0] = args;, the reference variable arg[0], which was referring to an array with two elements, is reassigned to an array (args) with three elements. |
5. |
What is the output of this program? class array_output { public static void main(String args[]) { char array_variable [] = new char[10]; for (int i = 0; i < 10; ++i) { array_variable[i] = 'i'; System.out.print(array_variable[i] + ""); } } } |
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Your Answer: Option (Not Answered) Correct Answer: Option D Explanation: None. |
6. |
Can 8 byte long data type be automatically type cast to 4 byte float data type? |
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Your Answer: Option (Not Answered) Correct Answer: Option A Explanation: Both data types have different memory representation that’s why 8-byte integral data type can be stored to 4-byte floating point data type. |
7. |
What is the output of this program? class rightshift_operator { public static void main(String args[]) { int x; x = 10; x = x >> 1; System.out.println(x); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option B Explanation: Right shift operator, >>, devides the value by 2. |
8. |
What is the output of this program? class Output { public static void main(String args[]) { int x , y = 1; x = 10; if (x != 10 && x / 0 == 0) System.out.println(y); else System.out.println(++y); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option B Explanation: Operator short circuit and, &&, skips evaluating right hand operand if left hand operand is false thus division by zero in if condition does not give an error. |
9. |
Which of these lines of code will give better performance? |
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Your Answer: Option (Not Answered) Correct Answer: Option C Explanation: Parentheses do not degrade the performance of the program. Adding parentheses to reduce ambiguity does not negatively affect your system. |
10. |
What is the output of this program? class Output { public static void main(String args[]) { final int a=10,b=20; while(a<b) { System.out.println("Hello"); } System.out.println("World"); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option D Explanation: Every final variable is compile time constant. |
11. |
What is the output of this program? class box { int width; int height; int length; } class mainclass { public static void main(String args[]) { box obj1 = new box(); box obj2 = new box(); obj1.height = 1; obj1.length = 2; obj1.width = 1; obj2 = obj1; System.out.println(obj2.height); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option A Explanation: When we assign an object to another object of same type, all the elements of right side object gets copied to object on left side of equal to, =, operator. |
12. |
In the below code, which call to sum() method is appropriate? class Output { public static int sum(int ...x) { return; } static void main(String args[]) { sum(10); sum(10,20); sum(10,20,30); sum(10,20,30,40); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option D Explanation: sum is a variable argument method and hence it can take any number as argument. |
13. |
Which of the following statements are incorrect? |
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Your Answer: Option (Not Answered) Correct Answer: Option C Explanation: finalize() method is called just prior to garbage collection. it is not called when object goes out of scope. |
14. |
What is the output of this program? class test { int a; int b; void meth(int i , int j) { i *= 2; j /= 2; } } class Output { public static void main(String args[]) { test obj = new test(); int a = 10; int b = 20; obj.meth(a , b); System.out.println(a + " " + b); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option A Explanation: Variables a & b are passed by value, copy of their values are made on formal parameters of function meth() that is i & j. Therefore changes done on i & j are not reflected back on original arguments. a & b remain 10 & 20 respectively. |
15. |
Which of these access specifier must be used for class so that it can be inherited by another sub class? |
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Your Answer: Option (Not Answered) Correct Answer: Option A Explanation: None. |
16. |
What is the output of this program? class Output { public static void main(String args[]) { int arr[] = {1, 2, 3, 4, 5}; for ( int i = 0; i < arr.length - 2; ++i) System.out.println(arr[i] + " "); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option B Explanation: arr.length() is 5, so the loop is executed for three times. |
17. |
What is the output of this program? class string_class { public static void main(String args[]) { String obj = "hello"; String obj1 = "world"; String obj2 = obj; obj2 = " world"; System.out.println(obj + " " + obj2); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option C Explanation: None. |
18. |
What is the output of this program? class A { public int i; public int j; A() { i = 1; j = 2; } } class B extends A { int a; B() { super(); } } class super_use { public static void main(String args[]) { B obj = new B(); System.out.println(obj.i + " " + obj.j) } } |
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Your Answer: Option (Not Answered) Correct Answer: Option A Explanation: Keyword super is used to call constructor of class A by constructor of class B. Constructor of a initializes i & j to 1 & 2 respectively. |
19. |
What is the output of this program? class Abc { public static void main(String[]args) { String[] elements = { "for", "tea", "too" }; String first = (elements.length > 0) ? elements[0]: null; } } |
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Your Answer: Option (Not Answered) Correct Answer: Option D Explanation: The value at the 0th position will be assigned to the variable first. |
20. |
What is the output of this program? class Output { public static void main(String args[]) { Object obj = new Object(); System.out.print(obj.getclass()); } } |
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Your Answer: Option (Not Answered) Correct Answer: Option C Explanation: None. |