Gson iterate jsonobject

https://stackoverflow.com/questions/31094305/java-gson-getting-the-list-of-all-keys-under-a-jsonobject

As of Gson 2.8.1 you can use keySet():

String json = "{\"key1\":\"val\", \"key2\":\"val\"}";

JsonParser parser = new JsonParser();
JsonObject jsonObject = parser.parse(json).getAsJsonObject();

Set<String> keys = jsonObject.keySet();

Since Java 8 you can use Streams as better looking alternative:

String str = "{\"key1\":\"val1\", \"key2\":\"val2\"}";

JsonParser parser = new JsonParser();
JsonObject jObj = (JsonObject) parser.parse(str);

List<String> keys = jObj.entrySet()
    .stream()
    .map(i -> i.getKey())
    .collect(Collectors.toCollection(ArrayList::new));

keys.forEach(System.out::println);

You can use JsonParser to convert your Json into an intermediate structure which allow you to examine the json content.

String yourJson = "{your json here}";
JsonParser parser = new JsonParser();
JsonElement element = parser.parse(yourJson);
JsonObject obj = element.getAsJsonObject(); //since you know it's a JsonObject
Set<Map.Entry<String, JsonElement>> entries = obj.entrySet();//will return members of your object
for (Map.Entry<String, JsonElement> entry: entries) {
    System.out.println(entry.getKey());
}