Sorting Hashmap by values?

Hey, so I have to sort a hashmap by its values. I've tried googling but the few things I found were quite complex, so I was hoping someone here could give me a simpler explanation.

What I want to do:

I have a config file with player uuids and a corresponding long value.
I want this to be sorted by the long value, from higher to lower, and I only need the top 20 values.

 

@timtower Thanks for your reply, I implemend it in my code but doesnt work.

This is what I have now. Problem: When testing this with my 2 accounts: AwesomeFishhy, and AFishhy, it displays only AFishhy as: 2. AFishhy: 0 days, 0 hours, 0 minutes, 0 seconds

The plugin.getDurationBreakdown is not the problem, as I have that perfectly working with another command.
Also, AwesomeFishhy doesnt show up as nr. 1.

Do you know why this happens, I can't figure it out.

Code:

public boolean onCommand(CommandSender sender, Command cmd, String s, String[] args) {

        if (cmd.getName().equalsIgnoreCase("zilanttop")) {

            // Get top20 long values (time played) and sort from high to low
            if (sender instanceof Player) {
                Player player = (Player) sender;
                plugin.updateTimePlayed();
                if (args.length == 0) {
                    int counter = 0;
                    HashMap<Player, Long> players = new HashMap<Player, Long>();
                    for (String key : plugin.getConfig().getConfigurationSection("players").getKeys(false)) {
                        counter++;
                        UUID pUuid = UUID.fromString(key);
                        Player p = Bukkit.getPlayer(pUuid);
                        players.put(p, plugin.getConfig().getLong(key));
                    }

                    HashMap<Player, Long> clone = new HashMap<Player, Long>(players);
                    HashMap<Player, Long> sorted = new HashMap<Player, Long>();
                    Long highest = (long) 0;
                    String highestP = "";
                    if (counter > 20) {
                        counter = 20;
                    }
                    for (int i = 0; i < counter; i++) {
                        for (Player key1 : clone.keySet()) {
                            Long value = players.get(key1);
                            if (value > highest) {
                                highest = value;
                                highestP = key1.getName();
                            }
                        }
                        clone.remove(Bukkit.getPlayer(highestP));
                        sorted.put(Bukkit.getPlayer(highestP), highest);
                    }
                    int counter2 = 0;
                    for (Player key2 : sorted.keySet()) {
                        player.sendMessage(plugin.prefix + " " + counter + ". " + key2.getName() + ": "
                                + plugin.getDurationBreakdown(sorted.get(key2)));
                    }
                } else {
                    player.sendMessage(plugin.prefix + " Too many arguments! /zilanttop");
                }
            } else {
                sender.sendMessage(plugin.prefix + " Only players can use this command!");
            }
        }

        return false;
    }