Generate all pairs of elements in an iterator, excluding matching pairs

PairPermutations.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;

public class PairPermutations {

  public static void main(String[] args) {
    Iterator<String> itemsIterator = Arrays.asList("1", "2", "3").iterator();
    List<String> itemsList = new ArrayList<>();
    itemsIterator.forEachRemaining(itemsList::add);

    List<String[]> pairs = itemsList.stream()
        .flatMap(item1 -> itemsList.stream()
            .filter(item2 -> !item1.equals(item2))
            .map(item2 -> new String[]{item1, item2}))
        .collect(Collectors.toList());

    pairs.stream().forEach(pair -> System.out.println(Arrays.toString(pair)));
  }

}