Thread: Constructor & container

I'd like to make working constructor creating a list filled with elements of the container.
I have a program:

import java.util.*;
 
class Utils {
 
    public static <T extends Comparable<T>>
    void print(XList<T> list) {
        for (T elem : list) {
            System.out.println(elem);
        }
    }
}
 
public class XList<T extends Comparable<T>>
        implements Iterable<T> {
    ArrayList<Double> v = new ArrayList<Double>();
    Collection<T> list;
 
    public XList(Collection<T> list) {
        this.list = list;
    }
 
    public static void main(String[] args) {
        ArrayList<Double> v = new ArrayList<Double>();
        v.add(new Double(1.0));
        v.add(new Double(5.0));
        v.add(new Double(3.0));
        XList<Double> list = new XList<Double>(v);
        Utils.print(list);
    }
 
    @Override
    public Iterator<T> iterator() {
        return new Iterator<T>() {
            int i = 0;
 
            @Override
            public boolean hasNext() {
                return i < list.size();
            }
 
            @Override
            public T next() {
                if (hasNext()) {
                    return list.get(i++);       //here is a mistake...
                }
                return null;
            }
        };
    }
}

Is there anyone who could help me write it correctly?

Thanks for the answer.
This is a part of the whole my exercise.
The idea would be to use as much as possible existing elements from this exercise.
I can do something like this:

package TestXList;
 
import java.util.ArrayList;
import java.util.Collection;
 
class XList<T extends Comparable<T>>{
 
    Collection<T> list;
 
    public XList(Collection<T> list) {
        this.list = list;
    }
}

and

package TestXList;
 
import java.util.ArrayList;
 
public class TestXList {
    public static void main(String[] args) {
        ArrayList<Double> v = new ArrayList<Double>();
        v.add(new Double(1.0));
        v.add(new Double(5.0));
        v.add(new Double(3.0));
        ArrayList<Double> list = new ArrayList<Double>(v);
        list.stream().forEach(System.out::println);
    }
}

but I can't use the iterator or the class Utils...