ScoreboardManager manager = Bukkit.getScoreboardManager();
Scoreboard board = manager.getNewScoreboard();
Objective objective = board.registerNewObjective("test", "dummy");
//Setting where to display the scoreboard/objective (either SIDEBAR, PLAYER_LIST or BELOW_NAME)
objective.setDisplaySlot(DisplaySlot.SIDEBAR);
//Setting the display name of the scoreboard/objective
objective.setDisplayName("Display Name");
Score score = objective.getScore(ChatColor.GREEN + "Kills:"); //Get a fake offline player
score.setScore(1);