I have a program that needed to consume a second API where the field names in the JSON response could be capitalized, or might not. We're using JsonNode to parse the responses, and this is a solution I came up with. I'm posting it here as it may help others - or could be improved with feedback.

lowercaseJsonNodeNames.java

private static JsonNode lowercaseNodeNames(JsonNode node) {
	ObjectMapper mapper = new ObjectMapper();
	ObjectNode loweredNode = mapper.createObjectNode();
	Iterator<String> fieldNames = node.fieldNames();
	
	while (fieldNames.hasNext()) {
		String currentName = fieldNames.next();
		JsonNode currentValue = null;
		if (node.get(currentName).isObject()) {
			// checking for nestedNode in currentNode
			JsonNode nestedNode = node.get(currentName);
			currentValue = lowercaseNodeNames(nestedNode);
		} else if (node.get(currentName).isArray()) {
			ArrayNode arrayNode = mapper.createArrayNode();

			for (int i = 0; i < node.get(currentName).size(); i++) {
				arrayNode.add(lowercaseNodeNames(node.get(currentName).get(i)));
			}
			currentValue = arrayNode;
		} else {
			currentValue = node.get(currentName);
		}
		// lowercase only the first character of the name
		loweredNode.put(Character.toString(currentName.charAt(0)).toLowerCase() + currentName.substring(1), currentValue);
	}
	return loweredNode;
}