Java bizarre.lang.ExceptionInInitializerError - JSoup

Dans mon dernier projet, j'utilise JSoup pour récupérer une page Web, obtenir tous les éléments avec la classe ".têtes de" et ensuite enregistrer des parties spécifiques d'un fichier. Lorsque je l'exécute, j'obtiens cette erreur:

java.lang.ExceptionInInitializerError
    at org.jsoup.nodes.Entities$EscapeMode.<clinit>(Entities.java:19) ~[?:?]
    at org.jsoup.nodes.Document$OutputSettings.<init>(Document.java:373) ~[?:?]
    at org.jsoup.nodes.Document.<init>(Document.java:18) ~[?:?]
    at org.jsoup.parser.TreeBuilder.initialiseParse(TreeBuilder.java:29) ~[?:?]
    at org.jsoup.parser.TreeBuilder.parse(TreeBuilder.java:42) ~[?:?]
    at org.jsoup.parser.HtmlTreeBuilder.parse(HtmlTreeBuilder.java:53) ~[?:?]
    at org.jsoup.parser.Parser.parseInput(Parser.java:30) ~[?:?]
    at org.jsoup.helper.DataUtil.parseByteData(DataUtil.java:94) ~[?:?]
    at org.jsoup.helper.HttpConnection$Response.parse(HttpConnection.java:603) ~[?:?]
    at org.jsoup.helper.HttpConnection.get(HttpConnection.java:195) ~[?:?]
    at de.zbs.advancedheads.main.AdvancedHeads.downloadDatabase(AdvancedHeads.java:48) ~[?:?]
    at de.zbs.advancedheads.main.AdvancedHeads.onEnable(AdvancedHeads.java:33) ~[?:?]
    at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:340) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugin(CraftServer.java:357) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.enablePlugins(CraftServer.java:317) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.reload(CraftServer.java:741) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.Bukkit.reload(Bukkit.java:535) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:25) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:641) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchServerCommand(CraftServer.java:627) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at net.minecraft.server.v1_8_R3.DedicatedServer.aO(DedicatedServer.java:412) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:375) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:653) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:556) [spigot-1.8.8-R0.1-SNAPSHOT-latest.jar:git-Spigot-fdc1440-53fac9f]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_73]
Caused by: java.lang.NullPointerException
    at java.util.Properties$LineReader.readLine(Unknown Source) ~[?:1.8.0_73]
    at java.util.Properties.load0(Unknown Source) ~[?:1.8.0_73]
    at java.util.Properties.load(Unknown Source) ~[?:1.8.0_73]
    at org.jsoup.nodes.Entities.loadEntities(Entities.java:236) ~[?:?]
    at org.jsoup.nodes.Entities.<clinit>(Entities.java:220) ~[?:?]
    ... 28 more

Mon code est le suivant:

private boolean downloadDatabase() {
    new File(path).mkdirs();
    try {
        Document doc = Jsoup.connect("http://heads.freshcoal.com/maincollection.php").get();
        Elements head = doc.select(".heads");
        System.out.println(head);
        for (Element e : head) {
            Attributes att = e.attributes();
            System.out.println(att);
            String command = att.get("data-clipboard-text");
            System.out.println(command);
            String remover = command.replace("/give @p skull 1 3 {display:{Name:\"", "");
            String name = remover.substring(0, 5);
            Bukkit.broadcastMessage(name);
            String texture = remover.substring(30, 50);
            Bukkit.broadcastMessage(texture);
        }
        return true;
    } catch (IOException e) {
        e.printStackTrace();
        return false;
    }
}

Oui, j'ai déjà vérifié si la bibliothèque jsoup est installée, je ne savais pas comment en faire une bibliothèque donc j'ai juste pris les sources et les ai mises dans mon projet.

Merci pour toute aide à l'avance!