ObjectDiff.java

public class ObjectDiff {

    private static final Logger LOG = LoggerFactory.getLogger(ObjectDiff.class);

    public Map<String, Map<String, Object>> getDiff(Object oldObject, Object newObject) {
        Map<String, Map<String, Object>> diff = new HashMap<>();

        if (oldObject == null && newObject != null) {
            Map<String, Object> objectDiff = new HashMap<>();
            String objectName = newObject.getClass().getSimpleName();

            objectDiff.put("old", oldObject);
            objectDiff.put("new", newObject);

            diff.put(objectName, objectDiff);
            return diff;
        } else if (oldObject != null && newObject == null) {
            Map<String, Object> objectDiff = new HashMap<>();
            String objectName = oldObject.getClass().getSimpleName();

            objectDiff.put("old", oldObject);
            objectDiff.put("new", newObject);

            diff.put(objectName, objectDiff);
            return diff;
        } else if (oldObject == null && newObject == null) {
            return diff;
        }

        for(Field newObjectField : newObject.getClass().getDeclaredFields()) {
            try {
                boolean newObjectAccessSettingsBkp = newObjectField.isAccessible();
                newObjectField.setAccessible(true);

                Field oldObjectField = oldObject.getClass().getDeclaredField(newObjectField.getName());
                boolean oldObjectAccessSettingsBkp = oldObjectField.isAccessible();
                oldObjectField.setAccessible(true);

                Object oldObjectFieldValue = oldObjectField.get(oldObject);
                Object newObjectFieldValue = newObjectField.get(newObject);

                if(hasChanges(oldObjectFieldValue, newObjectFieldValue)) {
                    Map<String, Object> objectDiff = new HashMap<>();

                    if(newObjectFieldValue instanceof BaseEntity) {
                        Map childDiff = getDiff(oldObjectFieldValue, newObjectFieldValue);
                        if(!childDiff.isEmpty()) {
                            diff.put(newObjectField.getName(), childDiff);
                        }
                    } else if (newObjectFieldValue == null || !newObjectFieldValue.equals(oldObjectFieldValue)) {
                        objectDiff.put("old", oldObjectFieldValue);
                        objectDiff.put("new", newObjectFieldValue);
                        diff.put(newObjectField.getName(), objectDiff);
                    }
                }

                newObjectField.setAccessible(newObjectAccessSettingsBkp);
                oldObjectField.setAccessible(oldObjectAccessSettingsBkp);
            } catch (NoSuchFieldException | IllegalAccessException e) {
                LOG.error("Could not get object diff. Reason: " + e.getMessage());
            }
        }

        return diff;
    }

    public boolean hasChanges(Object oldObject, Object newObject) {
        DiffNode diff = ObjectDifferBuilder.buildDefault().compare(newObject, oldObject);
        return diff.hasChanges();
    }

}