sortByFrequency

package ch.fhnw.claudemartin;

import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

public class SomeClass {

  public static void main(final String[] arrg) {
    final int[] arr = { 2, 5, 2, 8, 5, 6, 8, 8 };
    System.out.println(Arrays.toString(sortByFrequency(arr)));
  }

  static final int[] sortByFrequency(final int[] input) {
    final List<Integer> list = Arrays.stream(input).boxed().collect(Collectors.toList());
    final Comparator<Integer> comp = (a,b) -> Integer.compare(Collections.frequency(list, b), Collections.frequency(list, a));
    return Arrays.stream(input).distinct().boxed().sorted(comp).mapToInt(i -> i).toArray();
  }

}