org.mapdb.DBException$SerializationError when storing JSONArray in MapDB using ELSA Serialization

I have a class that store a Long value and JSONArray.

Class SomeClass {
    private Long longValue;
    private JSONArray jsonArray;
    //Default and parameterised constructors.
    //Getters and Setters.
}

I'm storing these values in a NavigableMap<?, SomeClass>. ? - String / Long. I get a treeMap from MapDB as follows:

private DB mapDB = MapDBUtil.getMapDB(); //Opening or creating and getting MapDB DB object
NavigableMap<Long,SomeClass> treeMap = mapDB.treeMap(treeName).keySerializer(Serializer.LONG).valueSerializer(Serializer.ELSA).createOrOpen();

When I try to add some value to the map obtained, say:

SomeClass instance = new SomeClass("Hello", jsonArray);
treeMap.put("test", instance);

I get org.mapdb.DBException$SerializationError. I figured the issue is due to serializing JSONArray. I want to either implement a custom serializer or use some other way to serialize and store this data. I tried implementing Serializable and also ElsaSerializer in 'SomeClass' but both of those don't seem to work. I have also tried to use Serializer.JAVA when Serializable interface is implemented but that doesn't work too. I'm not sure about what I'm doing wrong. Any help would be really appreciated.

I ended up fixing it by implementing a custom serializer and using it as follows:

Class SomeClassSerialzer extends GroupSerializerObjectArray<SomeClass> {
@Override
    public void serialize(DataOutput2 dataOutput2, SomeClass someClass) throws IOException {
        dataOutput2.writeLong(someClass.getLong());
        dataOutput2.writeUTF(threatSourceData.getJSONArray().toString());
    }

    @Override
    public SomeClass deserialize(DataInput2 dataInput2, int i) throws IOException {
        JSONArray jsonArray = null;
        Long longValue = dataInput2.readLong();
        try {
            categories = new JSONArray(dataInput2.readUTF());
        } catch (JSONException ignored) {
        }
        return new SomeClass(reputation, categories);
    }
}

When getting BTreeMap from MapDB, use the SomeClassSerialzer as follows:

NavigableMap<Long,SomeClass> treeMap = mapDB.treeMap(treeName).keySerializer(Serializer.LONG).valueSerializer(new SomeClassSerialzer()).createOrOpen();