Aquí tienes unos cuantos ejemplos de como ordenar una lista con stream.sorted().

1Ordenar una lista con Comparator.naturalOrder()

package com.cdlp.sorted;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class StreamApplication {

    public static void main(String[] args) {

        List < String > list = Arrays.asList("9", "A", "Z", "1", "B", "Y", "4", "a", "c");

        /* 
  List sortedList = list.stream()
   .sorted(Comparator.naturalOrder())
   .collect(Collectors.toList());
   
        List sortedList = list.stream()
   .sorted((o1,o2)-> o1.compareTo(o2))
   .collect(Collectors.toList());
  */

        List < String > sortedList = list.stream().sorted().collect(Collectors.toList());

        sortedList.forEach(System.out::println);
    }
}

Salida:

1
4
9
A
B
Y
Z
a
c

2Ordenar una lista con Comparator.reverseOrder()

package com.cdlp.sorted;

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

public class StreamApplication {

    public static void main(String[] args) {

        List list = Arrays.asList("9", "A", "Z", "1", "B", "Y", "4", "a", "c");

        /*
  List sortedList = list.stream()
   .sorted((o1,o2)-> o2.compareTo(o1))
   .collect(Collectors.toList());
  */
  
        List sortedList = list.stream()
   .sorted(Comparator.reverseOrder())
   .collect(Collectors.toList());

        sortedList.forEach(System.out::println);
    }
}

Salida:

c
a
Z
Y
B
A
9
4
1

3Ordenar objetos por atributo, orden natural

package com.cdlp.sorted;

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

public class StreamApplication {

    static List users = Arrays.asList(
            new User("C", 30),
            new User("D", 40),
            new User("A", 10),
            new User("B", 20),
            new User("E", 50));

    public static void main(String[] args) {
        
        /*List sortedList = users.stream()
            .sorted((o1, o2) -> o1.getAge() - o2.getAge())
            .collect(Collectors.toList());*/
   
        List sortedList = users.stream()
            .sorted(Comparator.comparingInt(User::getAge))
            .collect(Collectors.toList());
 
        sortedList.forEach(System.out::println);

    }

    static class User {

        private String name;
        private int age;

        public User(String name, int age) {
            this.name = name;
            this.age = age;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public int getAge() {
            return age;
        }

        public void setAge(int age) {
            this.age = age;
        }

        @Override
        public String toString() {
            return "User{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }
    }
}

Salida:

User{name='A', age=10}
User{name='B', age=20}
User{name='C', age=30}
User{name='D', age=40}
User{name='E', age=50}

4Ordenar objetos por atributo, orden inverso

List sortedList = users.stream()
    .sorted(Comparator.comparingInt(User::getAge)
    .reversed())
    .collect(Collectors.toList());

sortedList.forEach(System.out::println);

Salida:

User{name='E', age=50}
User{name='D', age=40}
User{name='C', age=30}
User{name='B', age=20}
User{name='A', age=10}