Nashorn - Java 8 - Error - HELP!

[sadiaas]

This is the error im getting when i launch the server:

Spoiler

And this is my code for my AbstractScriptManager:

Spoiler

package net.sf.odinms.scripting;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import javax.script.*;
import net.sf.odinms.client.MapleClient;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import jdk.nashorn.api.scripting.NashornScriptEngine;

public abstract class AbstractScriptManager {

private boolean nashorn = true;    
    
private ScriptEngineFactory sef;
protected static final Logger log = LoggerFactory.getLogger(AbstractScriptManager.class);

    protected AbstractScriptManager() {
        sef = new ScriptEngineManager().getEngineByName("javascript").getFactory();
    }

    protected NashornScriptEngine getScriptEngine(String path) {
        path = "scripts/" + path;
        File scriptFile = new File(path);
        if (!scriptFile.exists()) {
            return null;
        }
        NashornScriptEngine engine = (NashornScriptEngine) sef.getScriptEngine();
        try (FileReader fr = new FileReader(scriptFile)) {
            if (nashorn == true){
                engine.eval("load('nashorn:mozilla_compat.js');" + System.lineSeparator());
            }
            engine.eval(fr);
        } catch (final ScriptException | IOException t) {
            log.error("Error executing script.", t);
            return null;
        }

        return engine;
    }

    protected NashornScriptEngine getScriptEngine(String path, MapleClient c) {
        NashornScriptEngine engine = (NashornScriptEngine) c.getScriptEngine("scripts/" + path);
        if (engine == null) {
            engine = getScriptEngine(path);
            c.setScriptEngine(path, engine);
        }

        return engine;
    }

    protected void resetContext(String path, MapleClient c) {
        c.removeScriptEngine("scripts/" + path);
    }
}

I'm not really sure what the issue is at this point so i anyone could tell me
- in a possibily noob friendly way then I'm all ears xD!

FWI!
I'm using XiuzSource