Convert JSON to map with string keys and List<String> values

Document document = Document.parse(jsonString);
List<Document> countsArray = document.get("counts",List.class);
for (Document doc : countsArray){
    doc.keySet(); //keys
    doc.values(); //values
    for (Map.Entry entry : doc.entrySet()){
        // iterate over each pair
    }
}

JsonObject jsonObject = new JsonObject();

for (int i = 0; i < keys.length; i ++) {
    jsonObject.addProperty(keys[i], values[i]);
}

ObjectNode jsonObject = JsonNodeFactory.instance.objectNode();

for (int i = 0; i < keys.length; i ++) {
    jsonObject.put(keys[i], values[i]);
}

 Map<String, Float> map = mapper.readValue(tree, new TypeReference<Map<String, Float>>(){});