Multi Line Chart example

MultiLineChart.java

@Override
public void onEnable() {
    Metrics metrics = new Metrics(this);
    metrics.addCustomChart(new MultiLineChart("players_and_servers", new Callable<Map<String, Integer>>() {
        @Override
        public Map<String, Integer> call() throws Exception {
            Map<String, Integer> valueMap = new HashMap<>();
            valueMap.put("servers", 1);
            valueMap.put("players", Bukkit.getOnlinePlayers().size());
            return valueMap;
        }
    }));
}
// If you use the Copy & Paste Metrics classes, use `Metrics.MultiLineChart` instead