Java JSON traverses nested nodes and populates map

[
  {
    "_id": "63e744e785730f8b3eb1dda5",
    "index": 0,
    "isActive": true,
    "balance": "$3,310.75",
    "age": 24,
    "name": "Marsh Velasquez",
    "gender": "male",
    "address": "704 Mill Lane, Dunbar, Iowa, 477",
    "about": "Laboris esse veniam culpa magna sunt consequat culpa elit occaecat non labore id dolore occaecat.",
    "registered": "2018-04-29T02:17:14 -02:00",
    "latitude": 23.617941,
    "longitude": 153.026279,
    "tags": [
      "do",
      "incididunt",
      "sint",
      "qui",
      "nulla"
    ],
    "friends": [
      {
        "id": 0,
        "name": "Mcintosh Montoya"
      },
      {
        "id": 1,
        "name": "Odom Horne"
      }
    ],
    "greeting": "Hello, Marsh Velasquez! You have 6 unread messages.",
    "favoriteFruit": "strawberry"
  },

  {
    "_id": "63e744e73d9ce6418efd7391",
    "index": 1,
    "isActive": false,
    "balance": "$3,917.23",
    "age": 34,
    "name": "Annmarie Gates",
    "gender": "female",
    "address": "662 Franklin Avenue, Sanford, Virgin Islands, 9048",
    "about": "Deserunt reprehenderit ullamco aute pariatur id. Aute sint amet veniam nisi eiusmod dolor est labore.",
    "registered": "2014-10-12T03:12:05 -02:00",
    "latitude": -47.735057,
    "longitude": -88.535544,
    "tags": [
      "sunt",
      "elit",
      "sint",
      "nostrud"
    ],
    "friends": [
      {
        "id": 0,
        "name": "Sloan Snider"
      },
      {
        "id": 1,
        "name": "Elva Rush"
      },
      {
        "id": 2,
        "name": "Alana Hyde"
      }
    ],
    "greeting": "Hello, Annmarie Gates! You have 3 unread messages.",
    "favoriteFruit": "strawberry"
  }
]

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>JSONToFlatMap</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.14.2</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.14.2</version>
        </dependency>
    </dependencies>

</project>

package org.example;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ValueNode;

import java.io.IOException;
import java.io.InputStream;
import java.util.*;

public class MakeJSONToFlatMap {

    public static void main(String[] args) throws IOException {

        ObjectMapper mapper = new ObjectMapper();
        // We choose to use LinkedHashMap to preserve the order of the entries as in the JSON file
        Map<String, String> map = new LinkedHashMap<>();

        // Read the JSON from the resource folder
        try (InputStream is = MakeJSONToFlatMap.class.getClassLoader().getResourceAsStream("example_of_json.json")) {
            JsonNode jsonNode = mapper.readTree(is);

            // First call of the method which will traverse the JSON and for each node it will call itself
            getAllKeysUsingJsonNodeFields(jsonNode, "", map);

            map.forEach((k, v) -> System.out.println(k + "  : " + v));
        }
    }

    private static void getAllKeysUsingJsonNodeFields(JsonNode jsonNode, String parentPath, Map<String, String> map) {
        if (jsonNode.isObject()) {
            /**
             * If the jsonNode is Object node then call for every property
             * (nested node) the same method with updated parent path
             */
            Iterator<Map.Entry<String, JsonNode>> fieldIterator = jsonNode.fields();
            while(fieldIterator.hasNext())
            {
                var field = fieldIterator.next();
                getAllKeysUsingJsonNodeFields(field.getValue(), parentPath + "." + field.getKey(), map);
            }
        } else if (jsonNode.isArray()) {
            /**
             * If the jsonNode is Array node then get all inner nodes and
             * call the same method with updated parent path
             */
            ArrayNode arrayField = (ArrayNode) jsonNode;
            for(int index = 0; index < arrayField.size(); index++ )
            {
                getAllKeysUsingJsonNodeFields(arrayField.get(index), parentPath + "[" + index + "]", map);
            }
        } else if (jsonNode.isValueNode()) {
            /**
             * If the jsonNode is isValueNode then populate the map.
             * From the previous calls of the methods the parentPath will
             * have the updated value with the path until the current node
             */
            ValueNode node = (ValueNode) jsonNode;
            String value = node.asText();
            map.put(parentPath, value );
        } else {
            throw new IllegalStateException("Unknown type of node: " + jsonNode);
        }
    }
}