say, I made an arraylist in (public class class1(String args[]))

```
static List<Double> list1 = new ArrayList<Double>();

```

then I pass this arraylist to a function in (public static void main(String args[]))

```
biggestvalue(list1);

```

this is the function for example:

```
public static double biggestvalue(List<Double> list){
    Collections.sort(list);
    return list.get(list.size()-1);
}

```

I pass it into a function so that hopefully it will only sort list but not list1, but then list1 gets sorted as well, and I do not understand why that is.
Therefore, please explain to me why that is, and what solutions to this error are out there?