final/src/FileManager.java

//This class allows us to input and output flies useful for
//Inputing levels and making save data.
import java.io.*;
import java.util.Scanner;

// TODO: close scanner etc after use
public class FileManager {
    public static void writeFile(String fileLocation, String writeString) throws IOException {
        File newFile = new File(fileLocation);
        FileWriter fileWriter = new FileWriter(newFile);
        fileWriter.write(writeString);
        fileWriter.close();
    }

    // will create file if it doesn't exist
    public static String readFile(String fileLocation) throws IOException {
        File newFile = new File(fileLocation);
        if (newFile.createNewFile()) {
            return null;
        } else {
            Scanner fileReader = new Scanner(newFile);
            // using the delimiter \\Z reads the entire file at once
            return fileReader.useDelimiter("\\Z").next();
        }
    }

    public static Object readObjectFromFile(String fileLocation, String allowedObject) throws IOException, ClassNotFoundException {
        FileInputStream fileStream = new FileInputStream(fileLocation);
        SafeObjectInputStream objectStream = new SafeObjectInputStream(fileStream, allowedObject);
        return objectStream.readObject();
    }

    public static void writeObjectToFile(String fileLocation, Object o) throws IOException {
        FileOutputStream fileStream = new FileOutputStream(fileLocation);
        ObjectOutputStream objectStream = new ObjectOutputStream(fileStream);
        objectStream.writeObject(o);
    }
}