would someone clearly explain how this works. I'm new to this

Reference Semantics Mystery

The following program produces 4 lines of output. Write the output below, as it would appear on the console.

import java.util.*; // for Arrays class

public class Mystery {

public static void main(String[] args) {

int x = 1;

int[] a = new int[4];

x = x * 2;

mystery(x, a);

System.out.println(x + " " + Arrays.toString(a));

x = x * 2;

mystery(x, a);

System.out.println(x + " " + Arrays.toString(a));

}

public static void mystery(int x, int[] a) {

x = x * 2;

if (x > 6) {

a[2] = 14;

a[1] = 9;

} else {

a[0] = 9;

a[3] = 14;

}

System.out.println(x + " " + Arrays.toString(a));

}

}