java.io.File error Language class

package io.github.tivecs.lab.language;

import io.github.tivecs.lab.storage.yaml.ConfigManager;
import org.bukkit.ChatColor;
import org.bukkit.configuration.file.FileConfiguration;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Set;

public class Language extends ConfigManager {

    private FileConfiguration config;

    private String languageId, parentLanguageId;
    private boolean asDefaultLanguage = false;

    public Language(File languageFile){
        super(languageFile);

        this.config = getConfig();
        String fileName = languageFile.getName();
        if (fileName.endsWith(".yml")){
            languageId = fileName.substring(0, fileName.length() - 4);
        }else{
            languageId = fileName;
        }

    }

    public void set(String path, List<String> value) {
        super.set(path, value);
    }

    public void setIfNotExists(String path, List<String> value) {
        super.setIfNotExists(path, value);
    }

    @Override
    public void saveConfig() {
        if (config != null){
            HashMap<String, Object> data = getData();
            for (String path : getDataActivityHistory()){
                config.set("messages." + path, data.get(path));
            }
            getDataActivityHistory().clear();

            try {
                config.save(getFile());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    public void readConfig() {
        if (config != null){
            getData().clear();

            Set<String> childs = getChilds("messages", false);
            for (String path : childs){

                List<String> msg = config.getStringList("messages." + path);
                int size = msg.size();

                for (int i = 0; i < size; i++){
                    msg.set(i, ChatColor.translateAlternateColorCodes('&', msg.get(i)));
                }

                getData().put(path, msg);
            }
        }
    }

    public void readAttribute(){
        if (config != null){
            this.languageId = config.getString("attributes.language-id");
            this.parentLanguageId = config.getString("attributes.parent-language-id");
            this.asDefaultLanguage = config.getBoolean("attributes.as-default-language");
        }
    }

    public String getLanguageId() {
        return languageId;
    }

    public String getParentLanguageId() {
        return parentLanguageId;
    }

    public boolean isAsDefaultLanguage() {
        return asDefaultLanguage;
    }
}