Java Arrays

Which of the following is FALSE about arrays on Java

• A java array is always an object

• Length of array can be changed after creation of array

• Arrays in Java are always allocated on heap

Predict the output?

public class Main {

public static void main(String args[]) {

int arr[] = {10, 20, 30, 40, 50};

for(int i=0; i < arr.length; i++)

{

System.out.print(" " + arr[i]);

}

}

}

• 10 20 30 40 50

• Compiler Error

• 10 20 30 40

class Test {

public static void main(String args[]) {

int arr[2];

System.out.println(arr[0]);

System.out.println(arr[1]);

}

}

• 0

  0

• garbage value

  garbage value

• Compiler Error

• Exception

public class Main {

public static void main(String args[]) {

int arr[][] = new int[4][];

arr[0] = new int[1];

arr[1] = new int[2];

arr[2] = new int[3];

arr[3] = new int[4];

int i, j, k = 0;

for (i = 0; i < 4; i++) {

for (j = 0; j < i + 1; j++) {

arr[i][j] = k;

k++;

}

}

for (i = 0; i < 4; i++) {

for (j = 0; j < i + 1; j++) {

System.out.print(" " + arr[i][j]);

k++;

}

System.out.println();

}

}

}

• Compiler Error

• 0

  1 2

  3 4 5

  6 7 8 9

• 0

  0 0

  0 0 0

  0 0 0 0

• 9

  7 8

  4 5 6

  0 1 2 3

Which of the following is the correct way of importing an entire package ‘pkg’?

• import pkg.

• Import pkg.

• import pkg.*

• Import pkg.*

Which of the following is/are advantages of packages?

• Packages avoid name clashes

• Classes, even though they are visible outside their package, can have fields visible to packages only

• We can have hidden classes that are used by the packages, but not visible outside.

• All of the above

Which of these is a mechanism for naming and visibility control of a class and its content?

• Object

• Packages

• Interfaces

• None of the above

Which of this access specifies can be used for a class so that its members can be accessed by a different class in the same package?

• Public

• Protected

• No Modifier

• All of the mentioned

Arrays in Java are dynamically allocated using the . . . . operator.

• create

• dynamic

• arrayList

• new

Which of the following statements correctly declares a two-dimensional integer array?

• int Matrix[ ] = new int[5,4];

• int Matrix[ ]; Matrix = new int[5,4];

• int Matrix[ ][ ] = new int[5][4];

• int Matrix[ ][ ] = int[5][4];