multisort

gistfile1.txt

package your.package;

import org.junit.Test;

import java.util.AbstractMap;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.stream.Stream;

/**
 * Created by Konstantin Konyshev on 14/08/2017.
 */
public class Cross {

    @Test
    public void test() {
        String s = "бор сапог сарай арбуз болт бокс биржа бар";
        Map<String, List<String>> result =
                Stream.of(s.split(" "))
                        .sorted(Comparator.comparing((String e) -> e.substring(0, 1)).thenComparing(e -> e.length()).reversed().thenComparing(e -> e.toString()))
                        .map(word -> new AbstractMap.SimpleEntry<>(word.substring(0, 1), word))
                        .collect(java.util.stream.Collectors.groupingBy(
                                AbstractMap.SimpleEntry::getKey,
                                java.util.stream.Collectors.mapping(AbstractMap.SimpleEntry::getValue, java.util.stream.Collectors.toList()))
                        )

                ;
        System.out.println(result);
    }
}