java.io.NotSerializableException Libgdx

Question

I'm trying to implement a save feature for my LibGdx game. It's just for learning purposes for me so I'm trying to recreate the Fallout Shelter game on mobile phones, but just as a desktop version. When I attempt to save or load I get this error:

java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: com.badlogic.gdx.utils.Array

And here is the load method, which is called when the game launches and always results in error

private void Load() {
    try {
        // Open file to read from, named SavedObj.sav.
        FileInputStream saveFile = new FileInputStream("SaveGame.sav");

        // Create an ObjectInputStream to get objects from save file.
        ObjectInputStream save = new ObjectInputStream(saveFile);

        energy = (Integer) save.readObject();
        System.out.println(energy);
        food = (Integer) save.readObject();
        System.out.println(food);
        water = (Integer) save.readObject();
        System.out.println(water);
        maxEnergy = (Integer) save.readObject();
        System.out.println(maxEnergy);
        maxFood = (Integer) save.readObject();
        System.out.println(maxFood);
        maxWater = (Integer) save.readObject();
        System.out.println(maxWater);
        caps = (Integer) save.readObject();
        System.out.println(caps);
        maxDwellers = (Integer) save.readObject();
        System.out.println(maxDwellers);
        dwellers = (Array<Dweller>) save.readObject();
        //Close the save file
        save.close(); 
    } catch (Exception exc) {
        exc.printStackTrace(); // If there was an error, print the info.
    }
}

It always finds a problem with the line when I attempt to load the list of Dwellers (Saving has the same errors and finds fault in the same line)

dwellers = (Array<Dweller>) save.readObject();

Where it then gives the error mentioned above. The class this is in is using java.io.Serializable and has it implemented, as other questions like this have suggested, but I still get the same error whether I have it implemented or not.

Answer 1

The exception is saying that you are trying to serialize an instance of com.badlogic.gdx.utils.Array ... and you can't.

According to the javadoc , the Array class that you are attempting to serialize does not implement Serializable .

You haven't provided enough information for a proper diagnosis / fix, but I suspect that Dweller directly or indirectly uses the Array class, and that is the root cause. Possible solutions might be to mark the Array field transient, and / or implement custom serialization methods ( readObject , writeObject and so on).