MCQ Exam Test

Q1

Which one of the following is a valid statement?

A char[] c = new char();
B char[] c = new char[5];
C char[] c = new char(4);
D char[] c = new char[];

Q2

What is the result of compiling and running the following code? public class Test{ public static void main(String[] args){ int[] a = new int[0]; System.out.print(a.length); } }

A 0
B Compilation error, arrays cannot be initialized to zero size.
C Compilation error, it is a.length() not a.length
D None of the above

Q3

What is the purpose of the Arrays.sort() method in Java?

A To find the maximum element in an array.
B To search for an element in an array.
C To sort the elements of an array.
D To reverse the elements of an array.

Q4

Which of the following statements is true about ArrayLists in Java?

A ArrayLists can only store primitive data types.
B ArrayLists can have duplicate elements.
C ArrayLists are fixed in size.
D ArrayLists can only store Strings.

Q5

In Java, what is the purpose of the Arrays.equals() method?

A To check if two arrays are equal.
B To concatenate two arrays.
C To find the common elements between two arrays.
D To remove duplicate elements from an array.

Q6

What would be the result of attempting to compile and run the following code? public class HelloWorld{ public static void main(String[] args){ double[] x = new double[]{1, 2, 3}; System.out.println("Value is " + x[1]); } }

A The program has a compile error because the syntax new double[]{1, 2, 3} is wrong and it should be replaced by {1, 2, 3}.
B The program has a compile error because the syntax new double[]{1, 2, 3} is wrong and it should be replaced by new double[3]{1, 2, 3};
C The program has a compile error because the syntax new double[]{1, 2, 3} is wrong and it should be replaced by new double[]{1.0, 2.0, 3.0};
D The program compiles and runs fine and the output

Q7

Which method is used to add an element to the end of an ArrayList in Java?

A addElement()
B insertElement()
C append()
D add()

Q8

When you pass an array to a method, the method receives ________ .

A A copy of the array.
B A copy of the first element.
C The reference of the array.
D The length of the array.

Q9

How do you declare a multi-dimensional array in Java?

A int[][] matrix;
B int matrix[][];
C int matrix[2][2];
D All of the above

Q10

Which will legally declare, construct, and initialize an array?

A int [] myList = {};
B int [] myList = (5, 8, 2);
C int myList [] [] = {4,9,7,0};
D int myList [] = {4, 3, 7};

Q11

What will be the output? public class Test{ public static void main(String[] args){ int[] a = new int[4]; a[1] = 1; a = new int[2]; System.out.println("a[1] is " + a[1]); } }

A The program has a compile error because new int[2]
B The program has a runtime error because a[1] = null
C a[1] is 0
D a[1] is 1

Q12

How do you check if an element exists in an array or ArrayList in Java?

A Use the find() method.
B Use the search() method.
C Use the contains() method.
D Use the exists() method.

Q13

What will be the output? public class Test{ public static void main(String[] args){ int[] x = new int[3]; System.out.println("x[0] is " + x[0]); } }

A The program has a compile error because the size of the array wasn't specified when declaring the array.
B The program has a runtime error because the array elements are not initialized.
C The program runs fine and displays x[0] is 0.
D The program has a runtime error because the array element x[0] is not defined.

Q14

In Java, how do you find the maximum element in an array?

A Use a loop to compare each element with the maximum value found so far.
B Use the max() method.
C Use the findMax() method.
D Use the maximum() method.

Q15

How do you find the index of an element in an ArrayList named list in Java?

A list.getIndex(element);
B list.indexOf(element);
C list.find(element);
D list.search(element);

Q16

What happens when you try to access an element at an index that is out of bounds in an ArrayList in Java?

A It returns null.
B It throws an ArrayIndexOutOfBoundsException.
C It returns -1.
D It throws an IndexOutOfBoundsException.

Q17

Determine output: public class Test{ public static void main(String[] args){ int[] x = {1, 2, 3, 4}; int[] y = x; x = new int[2]; for(int i = 0; i < x.length; i++) System.out.print(y[i] + " "); } }

A 1 2 3 4
B 0 0 0 0
C 1 2
D 0 0

Q18

What is the output of the following code? public class Test{ public static void main(String args[]){ double[] myList = {1, 5, 5, 5, 5, 1}; double max = myList[0]; int indexOfMax = 0; for(int i = 1; i < myList.length; i++){ if(myList[i] > max){ max = myList[i]; indexOfMax = i; } } System.out.println(indexOfMax); } }

A 0
B 1
C 2
D 3

Q19

What is output of the following code: public class Test{ public static void main(String[] args){ int[] x = {120, 200, 016 }; for(int i = 0; i < x.length; i++) System.out.print(x[i] + " "); } }

A 120 200 16
B 120 200 14
C 120 200 016
D 016 is a compile error. It should be written as 16.

Q20

In Java arrays are

A objects
B object references
C primitive data type
D None of the above

Q21

Analyze the following code and choose the correct answer. int[] arr = new int[5]; arr = new int[6];

A The code has compile errors because the variable arr cannot be changed once it is assigned.
B The code has runtime errors because the variable arr cannot be changed once it is assigned.
C The code can compile and run fine. The second line assigns a new array to arr.
D The code has compile errors because we cannot assign a different size array to arr.

Q22

In Java, how do you remove an element at a specific index from an ArrayList named list?

A list.remove(index);
B list.delete(index);
C list.pop(index);
D list.splice(index);

Q23

What will be the output of the program? public class Test{ public static void main(String [] args){ String s1 = args[1]; String s2 = args[2]; String s3 = args[3]; String s4 = args[4]; System.out.print(" args[2] = " + s2); } } and the command-line invocation is C:Java> java Test 1 2 3 4

A args[2] = 2
B args[2] = 3
C args[2] = null
D An exception is thrown at runtime.

Q24

What is the purpose of the Arrays.fill() method in Java?

A To fill an array with a specified value.
B To find the number of elements in an array.
C To copy elements from one array to another.
D To sort the elements of an array.

Q25

Which method is used to remove all elements from an ArrayList in Java?

A removeAllElements()
B clear()
C remove()
D deleteAll()

java - Part 9

Which one of the following is a valid statement?

What is the result of compiling and running the following code? public class Test{ public static void main(String[] args){ int[] a = new int[0]; System.out.print(a.length); } }

What is the purpose of the Arrays.sort() method in Java?

Which of the following statements is true about ArrayLists in Java?

In Java, what is the purpose of the Arrays.equals() method?

What would be the result of attempting to compile and run the following code? public class HelloWorld{ public static void main(String[] args){ double[] x = new double[]{1, 2, 3}; System.out.println("Value is " + x[1]); } }

Which method is used to add an element to the end of an ArrayList in Java?

When you pass an array to a method, the method receives ________ .

How do you declare a multi-dimensional array in Java?

Which will legally declare, construct, and initialize an array?

What will be the output? public class Test{ public static void main(String[] args){ int[] a = new int[4]; a[1] = 1; a = new int[2]; System.out.println("a[1] is " + a[1]); } }

How do you check if an element exists in an array or ArrayList in Java?

What will be the output? public class Test{ public static void main(String[] args){ int[] x = new int[3]; System.out.println("x[0] is " + x[0]); } }

In Java, how do you find the maximum element in an array?

How do you find the index of an element in an ArrayList named list in Java?

What happens when you try to access an element at an index that is out of bounds in an ArrayList in Java?

Determine output: public class Test{ public static void main(String[] args){ int[] x = {1, 2, 3, 4}; int[] y = x; x = new int[2]; for(int i = 0; i < x.length; i++) System.out.print(y[i] + " "); } }

What is output of the following code: public class Test{ public static void main(String[] args){ int[] x = {120, 200, 016 }; for(int i = 0; i < x.length; i++) System.out.print(x[i] + " "); } }

In Java arrays are

Analyze the following code and choose the correct answer. int[] arr = new int[5]; arr = new int[6];

In Java, how do you remove an element at a specific index from an ArrayList named list?

What will be the output of the program? public class Test{ public static void main(String [] args){ String s1 = args[1]; String s2 = args[2]; String s3 = args[3]; String s4 = args[4]; System.out.print(" args[2] = " + s2); } } and the command-line invocation is C:Java> java Test 1 2 3 4

What is the purpose of the Arrays.fill() method in Java?

Which method is used to remove all elements from an ArrayList in Java?

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