Question

What is the output of the following?

class ChangeIt
{
static void doIt( int[] z )
{
z = null ;
}
}

class TestIt
{
public static void main ( String[] args )
{
int[] myArray = {1, 2, 3, 4, 5} ;

ChangeIt.doIt( myArray );

for (int j=0; j System ( myArray[j] + " " ) ;
}
}

Answer 1

The output of the given Java program will be the original values of the array 'myArray' which are 1, 2, 3, 4, 5. Setting the array to null in the doIt method only affects the local copy of the reference, not the actual array.

Step-by-step explanation:

The student has asked what the output is when running a Java program that contains a main method, which creates an array and then calls a static method that attempts to set that array to null. However, in Java, objects such as arrays are passed by reference to methods, but the reference itself is passed by value. So in this case, the method doIt is given a copy of the reference to the array, and setting z to null only affects that copy, not the actual array referred to by myArray in the main method.

Thus, when the for loop in the main method prints out the array, it will print the original values in the array: 1, 2, 3, 4, 5.

Intended Output:

1 2 3 4 5

The output of the given code will be the values 1 2 3 4 5. Although the method doIt in the ChangeIt class sets the parameter z to null, it does not affect the original array myArray. When the doIt method is called, a copy of the reference to myArray is passed, so any changes made to that reference inside the method will not reflect outside of it. Therefore, the for loop in the TestIt class will iterate through the original values of myArray and print them.