forEach will iterate over children of a JsonNode (converted to String when printed) and fieldNames() gets an Iterator<String> over keys. Here are some examples for printing elements of the example JSON:

JsonNode rootNode = mapper.readTree(option);

System.out.println("\nchoices:");
rootNode.path("choices").forEach(System.out::println);

System.out.println("\nAllKeys:");
rootNode.fieldNames().forEachRemaining(System.out::println);

System.out.println("\nChoiceSettings:");
rootNode.path("choiceSettings").fieldNames().forEachRemaining(System.out::println);

You'll probably need fields() at some point that returns an Iterator<Entry<String, JsonNode>> so you can iterate over key, value pairs.

You can use elements() method and check if value key exist then add the value to list.

Smaple code

ObjectMapper mapper = new ObjectMapper();
JsonNode jsonNode = mapper.readTree(data);

List<String> values = new ArrayList<>();
jsonNode.forEach(jsonObject -> jsonObject.elements().forEachRemaining(valueNode -> {
    if(valueNode.has("value"))
        values.add(valueNode.get("value").asText());
}));
System.out.println(values);

Output:

[http://www.wikidata.org/entity/Q42442324, http://www.wikidata.org/prop/direct/P21, Kiisu Miisu, http://www.wikidata.org/entity/Q43260736, http://www.wikidata.org/prop/direct/P21, Paddles]

If you're trying to find a key which is placed inside nested object, you may use findValue(String key) method which returns null if a value is not found by the given key:

ObjectMapper mapper = new ObjectMapper();
JsonNode rootNode= mapper.readTree(json);

String[] keys = {
    "id", "create_date", "versions_control_advanced", "name", "nofield"
};

for (String key : keys) {
    JsonNode value = rootNode.findValue(key);
    System.out.printf("Key %s exists? %s --> value=%s%n", key, value != null,
                    value == null ? null : value.asText());

}

Output:

Key id exists? true --> value=276625
Key create_date exists? true --> value=2020-06-22T16:19:07
Key versions_control_advanced exists? true --> value=false
Key name exists? true --> value=
Key nofield exists? false --> value=null

JsonNode's iterator() method

Same as calling elements(); implemented so that convenience "for-each" loop can be used for looping over elements of JSON Array constructs.

For ObjectNode, elements() is implemented to return field names

Method for accessing all value nodes of this Node, iff this node is a JSON Array or Object node. In case of Object node, field names (keys) are not included, only values. For other types of nodes, returns empty iterator.

This is not what you want. You want something like fields()

Method to use for accessing all fields (with both names and values) of this JSON Object.

which returns an Iterator<Map.Entry<String,JsonNode>>, where the Entry key is the name and the JsonNode is the value.

You have to cast your node to ObjectNode to be able to call fields (assuming it is an ObjectNode).

There are other, more aptly-named, methods like fieldNames() that give you all the key names, which you can then use with get(String) to retrieve values.

Your root node doesn't have a customerSessionId, it has a HotelListResponse. Get that first.

//other methods
public void basicTreeModelRead()
{
    JsonNode innerNode = rootNode.get("HotelListResponse"); // Get the only element in the root node
    // get an element in that node
    JsonNode aField = innerNode.get("customerSessionId");

    //the customerSessionId has a String value
    String myString = aField.asText();

    System.out.println("customerSessionId is:" + myString);
}

This prints

customerSessionId is:0ABAAA7A-90C9-7491-3FF2-7E2C37496CA2

With Jackson's tree model (JsonNode), you have both "literal" accessor methods (get), which returns null for missing value, and "safe" accessors (path), which allow you to traverse "missing" nodes. So, for example:

JsonNode root = mapper.readTree(inputSource);
int h = root.path("response").path("history").getValueAsInt();

which would return the value at the given path, or, if the path is missing, 0 (default value).

But more conveniently, you can just use JSON pointer expression:

int h = root.at("/response/history").getValueAsInt();

There are other ways too, and often it is more convenient to model your structure as a Plain Old Java Object (POJO). Your content could fit something like:

public class Wrapper {
  public Response response;
} 
public class Response {
  public Map<String,Integer> features; // or maybe Map<String,Object>
  public List<HistoryItem> history;
}
public class HistoryItem {
  public MyDate date; // or just Map<String,String>
  // ... and so forth
}

and if so, you would traverse the resulting objects just like any Java object.

You should treat the Value of you json object as a new JSONObject, which is already the case. Or more, the value in your case is an array of Json Objects.

So you can use:

JSONObject jsonObj = new JSONObject(field.getValue());

Or if you are not sure if it's an array or an object, please take a look on this link.