How does reference variable work when adding it to list

Issue

I was solving this leetcode when I was baffled by the solution.

class Solution {
    public int[][] merge(int[][] intervals) {
        Arrays.sort(intervals, (a,b)->Integer.compare(a[0],b[0]));
        int[] newInterval = intervals[0];
        List<int[]> list = new ArrayList<>();
        list.add(newInterval);
        for(int[] interval:intervals){
            if(newInterval[1]>=interval[0]){
                //newInterval values can be changed because we add a "reference variable" newInterval to the list
                //so if it is changed, it is updated in the list
                newInterval[1] = Math.max(newInterval[1],interval[1]); 
            }
            else{
                newInterval = interval;
                list.add(newInterval);
            }
        }
        return list.toArray(new int[list.size()][]);
    }
}

The solution added an integer array to the list first, then changed some values of that array then the list had that updated array inside it. How does that work?

Explanation

What we added to our list is not the actual array object itself, but the reference to it. So when the object is altered, since list has the reference to that object, it gets the updated object reference.

But once we change that reference to that object in that else statement, we drop the reference to the old object and link it with a new one. So the old object is “finalised” inside the list.