A very simple search implementation for Jackson JsonNodes using recursive DFS

gistfile1.java

private JsonNode searchForEntity(JsonNode node, String entityName) {
    // A naive depth-first search implementation using recursion. Useful
    // **only** for small object graphs. This will be inefficient 
    // (stack overflow) for finding deeply-nested needles or needles 
    // toward the end of a forest with deeply-nested branches.
    if (node == null) {
        return null;
    }
    if (node.has(entityName)) {
        return node.get(entityName);
    }
    if (!node.isContainerNode()) {
        return null;
    }
    for (JsonNode child : node) {
        if (child.isContainerNode()) {
            JsonNode childResult = searchForEntity(child, entityName);
            if (childResult != null && !childResult.isMissingNode()) {
                return childResult;
            }
        }
    }
    // not found fall through
    return null;
}
  
  // Usage: 
  // Given the following JSON:  {"d":{"EntitySets":["BusinessTripView","Person","BusinessTrip"]}}
  // searchForEntity(rootJsonNode, "EntitySets"); # returns the container node for the search key, in this case ["BusinessTripView","Person","BusinessTrip"]

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If you have the full path of the entity you want to search for, you can do a breadth first search instead, right?
E.g. if you have {"a": {"b": "some text"}, "c": {"d": "some other text"}}, and we want to get a.c.d