Find max int in a collection in java without using streams

NoStreams.java

public Integer max(Collection<Integer> collection) {
    if( collection == null || collection.isEmpty() ) return null;
    Iterator<Integer> i = collection.iterator();
    int max = i.next();
    while (i.hasNext()) {
        int n = i.next();
        if (max < n) max = n;
    }
    return max;
}

//usage
List<Integer> list = ...;
Integer m = max(list);
int maximum = (m == null) ? 0 : m.intVal();