Incrementing with Methods in Java & (Added) Array Processing

Question

I have a question about Java:

public class Tester {

  private int[] testArray = {3, 4, 5};

  public void increment(int n) {

       n++;
  }
  public void firstTestMethod() {
       for(int i = 0; i < testArray.length; i++) {
            increment(testArray[i]);
            System.out.print(testArray[i] + " ");
       }
  } 
}

The output produced when invoking firstTestMethod for a Tester object is 3 4 5. Could someone please help explain why? Thank you!

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Hi all,

Could anyone take a look at this other problem? The correct answer is C, but I just don't understand! The link to the picture is below.

Thanks in advance!

Answer is C