Core Java - Interview Questions and Answers for 'Array' | Search Interview Question

Interview Questions and Answers - Order By Newest

Q61. Is this code valid

String[] strArray = new String[2];
strArray.length = 5;

Ans. It will give compile time error saying "The final field array.length cannot be assigned"

Arrays once initialized cannot be resized.

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Q62. What is the problem with this code

String[] strArray = new String[2];
strArray[0] = 5;

Core Java

Ans. We are trying to add an integer element to an array of String. Will give compile time error.

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Q63. Will this give compile time error ?

Object[] strArray = new String[2];
strArray[0] = 5;

Core Java

Ans. No. But It will throw ArrayStoreException at runtime.

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Q64. Write a Program to Find the maximum sum of the sub array ?

Data Structure

^{This question was recently asked at 'Reddit'.This question is still unanswered. Can you please provide an answer.}

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Q65. Difference between List and ArrayList ?

Core Java

Ans. List is an interface whereas ArrayList is an implementation of List.

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Q66. difference between ArrayList and array ?

Core Java

Ans. ArrayList is a variable length collection class whereas arrays are fixed length primitive structure.

We can use generics with arraylist but not with arrays.

We can store primitive data types within arrays but can't with ArrayList. In ArrayList that needs to be converted to Wrapper objects.

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Q67. Difference between ArrayList and HashSet ?

Core Java

Ans. ArrayList is a list , i.e an implementation of List interface whereas HashSet is a Set and an implementation of Set interface.

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Q68. Write a program to make an array act as a set.

Core Java

Ans. public Set convertArrayToList(T array[]) {
Set set = new HashSet<>(Arrays.asList(array));
return set;
}

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Q69. How can we create an arraylist of unique values ?

Core Java

Ans. We can put the value in a set to enforce uniqueness and then dum those value into an arraylist.

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Q70. What will be the output of exceuting main method ?

public static void main(String[] args){
      List list = new ArrayList();
      list.add(1);
      list.add(2);
      list.add(3);
      System.out.println(list);
   }

Core Java

a. 1,2,3

b. Order cannot be determined

c. compilation error

d. 3,2,1

Ans.a. 1,2,3

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