Interview Questions and Answers - Order By Newest Q31. why aren't arrays better than array list ? Core Java
Ans. 1. Arrays don't provide any built in support for sorting searching like operation and we need to do it explicitly.
2. It can hold only homogeneous objects,
3. We have to reserve memory as no dynamic expansion allowed. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  arraylist  arrays vs arraylist Asked in 3 Companies Q32. Why iterators of an array list are fail fast ? Core Java
Ans. Because it's access isn't synchronized and hence access / modification by multiple threads may lead to inconsistent state. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  fail fast  arraylist  collections Q33. What problem we could have with ArrayList which aren't possible with Vectors ? Core Java
Ans. ArrayLists aren't synchronized and hence doesn't allow synchronized access. As multiple threads can access an arraylist in parallel, it may result in an inconsistent state. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  vector  arraylist  list  collections Basic Q34. What is the quickest way to find count of duplicate elements in an arraylist, without using iteration or loops ? Core Java
Ans. We can copy the elements to a Set and then find the difference of count between ArrayList and Set. As Set don't allow duplicates , they will be removed in the set. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  collections  arraylist  set Q35. Why do we pass an array of strings to main method ? Core Java
Ans. Array of strings in the main method are the list of arguments or parameters which are sent to the application / program. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  main method   main method string array argument Q36. What does the following initialization mean ?
ArrayList<LinkedList> traversalPaths = new ArrayList<LinkedList>();
What could be the use of such a collection. Core Java
Ans. Initialize an ArrayList that will hold LinkedLists i.e every element of the arraylist will be a linked list.
Such collection could be used in algorithms that require first random access and then sequential traversal. For example - Storing traversal paths for a graph wherein we can start from any vertex. Implementing dictionary with each arraylist element holding staring with character and then linked list holding duplicate words. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  collections  linkedlist  arraylist Q37. What will the following code print ?
int x[] = new int[5];
x[0] = 1;
x[1] = 2;
for(int count=0;count<x.length;count++){
System.out.println(x[count]);
} Core Java
Ans. 1
2
0
0
0
As arrays are not dynamically expanded , we have declared the array for size 10. As we have only initialized only 2 values , it will print rest as their default values. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays Q38. What will the following code print
int x[] = new int[5];
x[0] = 1;
x[1] = 2;
for(int count=0;count<=x.length;count++){
System.out.println(x[count]);
} Core Java
Ans. 1
2
0
0
0
ArrayIndexOutOfBoundException: 5
As array index starts with 0 and ends with the index of (size - 1), the index 5 is inaccessible for the array and hence will throw the exception. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays Q39. How can we convert String into Char array and vice versa ? Core Java
Ans. There is a method toCharArray() within String class that can be used to convert string to char array.
string.toCharArray();
String class has an argument constructor that takes a char array and create a string
new String(charArray); Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  string  char array Q40. How can we convert a character or a character array into a String ? Core Java
Ans. String has an argument constructor that take char array as argument and creates a string.
There is no constructor available with String that takes in a character and creates a String. We can use StringBuilder which has a char argument constructor. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  character  char  char array  String  char to String  char array to String Q41. Which of the two - Arrays or LinkedList - is a better data structure for implementing Queue ? and Why ? Data Structure
This question is still unanswered. Can you please provide an answer. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  Arraylist  linkedlist  queue  collections Q42. Write an efficient program for printing k largest elements in an array. Elements in array can be in any order. Data Structure
This question was recently asked at 'Amazon'.This question is still unanswered. Can you please provide an answer. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  coding  code Asked in 1 Companies Q43. Which of the following - arrays or LinkedList allow elements to be accessed using index and how ? Data Structure
Ans. Arrays allows elements to be accessed directly using the index.
As Array elements are stored in continuous memory locations it's very easy to find the memory address of any element using the formula as following
Memory Address of Array start or index 0 + ( Size of array element * Index ) Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  linkedlist Q44. Find Intersection/union between two arrays. Core Java
This question was recently asked at 'Bristlecone,Amazon Lab126,Amazon,Microsoft,Facebook,NCR,Google'.This question is still unanswered. Can you please provide an answer. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  code  coding Asked in 7 Companies   frequent Ans. https://www.geeksforgeeks.org/arrays-sort-in-java-with-examples/ Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  array  sorting Asked in 16 Companies basic   frequent This question is still unanswered. Can you please provide an answer. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays Q47. Can we change the size of array once created ? Core Java
Ans. No. Arrays cannot resize dynamically. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  array  array size Basic Ans. It's an exception that is thrown when we attempt to add value of an incompatible type to an array.
For example -
Object[] strArray = new String[2];
strArray[0] = 5;
In this code, strArray reference of type Object has currently been assigned the String array but at line 2 we are trying to add an integer value. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays   ArrayStoreException Q49. What is an anonymous array in Java ? Core Java
This question is still unanswered. Can you please provide an answer. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  anonymous arraysAns. an array of different sizes Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  jagged arrays Q51. Are Arrays treated like primitives or like objects in Java ? Core Java
This question is still unanswered. Can you please provide an answer. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays Q52. How can we check equality for Arrays in Java ? Core Java
Ans. You call the method java.util.Arrays.equals(Object[] a, Object[] a2)? Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arraysAns. Yes Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  concurrency Asked in 1 Companies Q54. What is the time and space complexity for different operations for arrays ? Core Java
This question is still unanswered. Can you please provide an answer. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays This question is still unanswered. Can you please provide an answer. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays vs linkedlist Q56. Can we have 3 dimensional arrays in Java ? Core Java
Ans. Yes Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays Q57. Can we make array volatile in Java ? Core Java
Ans. Yes, you can make an array (both primitive and reference type array e.g. an int array and String array) volatile in Java but only changes to reference pointing to an array will be visible to all threads, not the whole array Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  volatile Q58. Is this array declaration correct ? If not , Why ?
String[] strArray = new String[]; Core Java
Ans. No, We haven't specified the size of array to be initialized. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  array initialization Q59. Is this array initialization correct ? If Yes, What will be the size of array ?
String[] strArray = new String[]{"Buggy","Bread"}; Core Java
Ans. Yes, size of the array will be 2. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  array initialization Q60. Is this array initialization correct ? If Yes, What will be the size of array ?
String[] strArray = new String[3]{"Buggy","Bread"}; Core Java
Ans. No. It will result in error saying "Cannot define dimension expressions when an array initializer is provided" Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  arrays  array initialization