Best way to compare 2 JSON files in Java

Question

How would you suggest this task is approached?

The challenge as i see it is in presenting diff information intelligently. Before i go reinventing the wheel, is there

Answer 1

I recommend the zjsonpatch library, which presents the diff information in accordance with RFC 6902 (JSON Patch). You can use it with Jackson:

JsonNode beforeNode = jacksonObjectMapper.readTree(beforeJsonString);
JsonNode afterNode = jacksonObjectMapper.readTree(afterJsonString);
JsonNode patch = JsonDiff.asJson(beforeNode, afterNode);
String diffs = patch.toString();

This library is better than fge-json-patch (which was mentioned in another answer) because it can detect items being inserted/removed from arrays. Fge-json-patch cannot handle that (if an item is inserted into the middle of an array, it will think that item and every item after that was changed since they are all shifted over by one).