Java Array Basics

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

Find the output

class Test {

public static void main(String args[]) {

int arr[2];

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

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

}

}

• Compile error

• Exception

• Garbage Value

  Garbage Value

• 0

  0

Find the output

class Test {

public static void main(String args[]) {

int arr [ ] = new int[2];

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

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

}

}

• Compile error

• Exception

• Garbage Value

  Garbage Value

• 0

  0

Output of following Java program?

class Test{

public static void main (String[] args) {

int arr1[] = {1, 2, 3};

int arr2[] = {1, 2, 3};

if (arr1 == arr2)

System.out.println("Same");

else

System.out.println("Not same");

}}

• Same

• Not same

• Error

class Test{

public static void main (String[] args) {

int arr1[] = {1, 2, 3};

int arr2[] = {1, 2, 3};

if(arr1.equals(arr2))

System.out.println("Same");

else

System.out.println("Not same");

}}

• Same

• Not same

• Error

What is the length of the following array: byte[] data = { 12, 34, 9, 0, -62, 88 };

• 1

• 5

• 6

• 12

Does a programmer always know how long an array will be when the program is being written?

• Yes---the program will not compile without the length being declared.

• No---the array object is created when the program is running, and the length might change from run to run.

• Yes---otherwise the program will not run correctly.

• No---arrays can grow to whatever length is needed.

class Demo1

{

public static void main(String args[])

{

int i[] = new int[0];

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

}

}

• 0

• Garbage Value

• Exception

class Demo1

{

public static void main(String args[])

{

int i[] = new int[10];

System.out.println(i[10]);

}

}

• 0

• Garbage Value

• Out-of-bounds exception

• Error

_________________ is a collection of elements used to store the same type of data.

• Array
• Switch
• Case
• Loop