Using JsonPath how can I get the inner value of these json objects

Question

Say I have some json like this that I am parsing with JsonPath :

{
  A: {key: "1"}
  B: {key: "1"}
  C: {key: "1"}
  D: {key: "1"}
  E: {key: "1"}
}  

or

{
  A: {key: "7"}
  B: {key: "7"}
  E: {key: "7"}
  G: {key: "7"}
}  

A, B, C, D, E, ..., etc can be any tag and are not regularly named. However, key always has the same value in each of the objects. Using a JsonPath query how can I get the value of key ? To be clear, the input should be that json and the output should be a single string containing the value of key

Answer 1

One option is to use $..key . This will return a List of values.
Then we need to use 'Stream API` to get an element out of it.

List<?> result = JsonPath.parse(s1)
                      .read("$..key", List.class);

result.stream()
      .findAny()
      .ifPresent(System.out::println);