Parser.java

    private TreeMap unserializeTreeMap(String fileName) {
        
        TreeMap map = new TreeMap<>();
        
        if (Parser.class.getResourceAsStream("/resource/serialized/" + fileName) != null) {

            try (InputStream in = Parser.class.getResourceAsStream("/resource/serialized/" + fileName); 
                 ObjectInputStream ois = new ObjectInputStream(in)) {            

                    map = (TreeMap) ois.readObject();            
            }        
            catch(Exception e) {
                e.printStackTrace();
            }  
        }
        
        return map;
    }
    
    private boolean serializeTreeMap(String fileName, TreeMap map) {
                
        URL resourceUrl = Parser.class.getClass().getResource("/resource/");
        
        try (FileOutputStream output = new FileOutputStream(resourceUrl.getFile() + "serialized/" + fileName);
             ObjectOutputStream o = new ObjectOutputStream(output)) {            
            
            o.writeObject(map);            
            
            return true;
        }        
        catch(Exception e) {
            e.printStackTrace();
        }  
        
        return false;
    }