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Java Array Declarations(Interview Questions)

  1. Can the following be declared with arrays in Java?
    int [][] globalArray = new int [3][];

    Yes. As a counter example the following line of code is incorrect and will result in a compiler error.
    int [][] array1 = new int[][];

    A minimum of 1 dimension is required when declaring arrays in Java.

  2. Write a Java constructor that accepts 2 array arguments.

    public class ArrayDemo {
     private int[] num1 = new int[3];
     private int[] num2 = new int[3];
     public ArrayDemo() { };
     public ArrayDemo(int[] array1, int[] array2) {
      this.num1 = array1;
      this.num2 = array2;
     public static void main(String[] args) {
      ArrayDemo ad1 = new ArrayDemo(new int[] {1,2,3} ,new int[] {1,2,3} );

  3. Can a constructor take a) arrays b) objects as parameters?


  4. What are arguments when calling a method?

    Arguments are the elements you specify between the parentheses when you are invoking a method. The parameters are the elements in the methods signature.

  5. What is static import?

    Answer: static import enables access to static members of a class without need to qualify it by the class name.

  6. How can you think of each of the elements in the primeArray?
    int [][] primeArray = {{1,3,5}, { 7,11,13}, { 17, 19, 23}};

    Each of the 3 elements in the primeArray is a reference variable to an int array.

  7. How do you create an anonymous array in Java.

    class AnonymousArray{
     static void print(int a[]) {
      for(int i=0;i<a.length;++i)
       System.out.print(a[i]+" ");
     static void print(int a[][]) {
      for(int i=0;i<a.length;++i){
       for(int j=0;j<a[i].length;++j)
        System.out.print(a[i][j]+" ");

     public static void main(String...s){
      //1d anonymous array 
      print(new int[]{11,23,31,43});
      System.out.println("\n Anonymous Array");
      //2d anonymous array 
      print(new int[][]{{2,3},{5,7},{11,13}});  

  8. How can you create an anonymous array for an array of int?

    int[] testScores;
    testScores = new int[] {4,7,2};

  9. Which primitive datatypes can an array of int hold?

    a) byte b) char c) short.

  10. What types of data can be assigned to an array?

    Any object that passes the "IS-A" test for the declared array type can be assigned to an element of that array.