A simple no-flashing scoreboard manager with rows up to 32 chars

NoFlash.java

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.entity.Player;
import org.bukkit.plugin.Plugin;
import org.bukkit.scheduler.BukkitRunnable;
import org.bukkit.scoreboard.DisplaySlot;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Scoreboard;
import org.bukkit.scoreboard.Team;

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

public class NoFlash extends BukkitRunnable {

    private final Scoreboard board = Bukkit.getScoreboardManager().getNewScoreboard();
    private final Objective obj = board.registerNewObjective("noflash", "dummy");
    private Team[] teams;
    private ChatColor next = ChatColor.RED;
    private int max;
    private String player;
    private ScoreboardTextProvider textProvider;

    private List<String> last, list;
    private List<ScoreboardRow> rows;

    public static String DONOTUPDATE = "§6§a§r";

    private NoFlash(Player p, ScoreboardTextProvider textProvider, int max) {
        this.player = p.getName();
        this.textProvider = textProvider;
        setTitle(textProvider.getScoreboardTitle());
        obj.setDisplaySlot(DisplaySlot.SIDEBAR);

        if(max > 16)
            max = 16;
        this.max = max;

        teams = new Team[max];

        for(int i = 0; i < max; i++){
            teams[i] = board.registerNewTeam("team" + (i + 1));
            teams[i].addPlayer(Bukkit.getOfflinePlayer(ChatColor.values()[i].toString() + ChatColor.RESET));
        }

        setList(textProvider.getScoreboardText(p));
        p.setScoreboard(board);
    }

    private NoFlash setList(List<String> list){
        if(list.size() > max)
            return this;

        if(this.list != null)
            this.last = new ArrayList<>(this.list);
        this.list = list;

        rows = list.stream().map(ScoreboardRow::new).collect(Collectors.toList());
        return this;
    }

    private NoFlash setTitle(String title){
        if(title.length() > 32)
            title = title.substring(0, 32);

        obj.setDisplayName(title);
        return this;
    }

    @Override
    public void run() {
        Player p = Bukkit.getPlayerExact(player);
        if(p == null){
            cancel();
            return;
        }

        if(!textProvider.getScoreboardText(p).equals(last)){
            setList(textProvider.getScoreboardText(p));
        }

        if(!textProvider.getScoreboardTitle().equals(obj.getDisplayName())){
            setTitle(textProvider.getScoreboardTitle());
        }

        if(next == ChatColor.RED) {
            next = ChatColor.BLUE;
        } else {
            next = ChatColor.RED;
        }

        int size = list.size() <= max ? list.size() : max;

        if(list != null){
            if(last != null && last.size() > list.size()){
                for(int k = max - 1; k > last.size() - list.size(); k--){
                    board.resetScores(teams[max - k - 1].getPlayers().iterator().next());
                }
            }

            for(int i = 0; i < list.size(); i++) {
                if(list.get(i).equals(DONOTUPDATE))
                    continue;

                ScoreboardRow row = rows.get(i);
                teams[size - i - 1].setPrefix(row.getPrefix());
                teams[size - i - 1].setSuffix(row.getSuffix());

                obj.getScore(teams[size - i - 1].getPlayers().iterator().next()).setScore(size - i);
            }
        }
    }

    public static NoFlash start(Plugin pl, Player p, ScoreboardTextProvider textProvider, int max){
        NoFlash nf = new NoFlash(p, textProvider, max);
        nf.runTaskTimer(pl, 1L, 5L);
        return nf;
    }

    public static NoFlash start(Plugin pl, Player p, ScoreboardTextProvider textProvider){
        return start(pl, p, textProvider, 16);
    }

    public void stop(){
        cancel();
    }

    public interface ScoreboardTextProvider {

        List<String> getScoreboardText(Player p);
        String getScoreboardTitle();

    }

    private class ScoreboardRow {

        private String prefix, suffix;

        public ScoreboardRow(String row){
            if(row.length() <= 16) {
                prefix = row;
                suffix = "";
            } else {     //up to 16+16, color pair is in single part
                int cut = findCutPoint(row, 16);
                prefix = row.substring(0, cut);
                suffix = row.substring(cut, cut + (cut + 16 <= row.length() ? cut + 16 : row.length() - cut));
            }
        }

        private int findCutPoint(String s, int max){
            for(int i = max; i > 0; i--){
                if(s.charAt(i-1) == ChatColor.COLOR_CHAR && ChatColor.getByChar(s.charAt(i)) != null)
                    continue;
                return i;
            }
            return 16;
        }

        public String getPrefix() {
            return prefix;
        }

        public String getSuffix() {
            return suffix;
        }
    }

}

May contain bugs now, look at supported version of NoFlashPacket instead
https://gist.github.com/serega6531/4acd23ac188c8c568287