Converting JSON to Java Map using Jackson

This tutorial demonstrates how to convert a JSON string into a Java Map using Jackson’s ObjectMapper. We will show a basic Java main Class to convert a sample JSON String. Then, we will simplify the classpath set up using JBang.


  • Basic understanding of Java programming.
  • Jackson library added to your project’s dependencies.


1. Include Jackson Dependency

Make sure to include the Jackson dependencies in your project. If you’re using Maven, add the following to your pom.xml file:

    <version>2.16.0</version> <!-- Replace with the latest version -->

Create a Java Class

Create a Java class where you’ll perform the conversion from JSON to a Java Map. Let’s name the class JSONToMap.

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.HashMap;
import java.util.Map;

public class JSONToMap {
    public static void main(String[] args) {
        // Sample JSON String
        String jsonString = "{\"name\":\"John Doe\",\"age\":30,\"city\":\"New York\"}";

        // Initialize ObjectMapper
        ObjectMapper objectMapper = new ObjectMapper();

        // Convert JSON to Map
        try {
            // Read JSON string and map it to a Java Map
            Map<String, Object> resultMap = objectMapper.readValue(jsonString, HashMap.class);

            // Print the generated Map
            System.out.println("Generated Map: ");
            for (Map.Entry<String, Object> entry : resultMap.entrySet()) {
                System.out.println(entry.getKey() + " : " + entry.getValue());
        } catch (JsonProcessingException e) {

3. Run the Code

Replace the jsonString variable with your actual JSON content. Execute the code, and it will convert the JSON string into a Java Map using Jackson’s ObjectMapper.

Run the example with JBang

Finally, if you want to run the above example as a Java script command, we recommend using JBang. For more info about JBang check this article: JBang: Create Java scripts like a pro

By using JBang, you can skip the project creation and just include the dependency on top of the Java Class:

//usr/bin/env jbang "$0" "$@" ; exit $?
//DEPS com.fasterxml.jackson.core:jackson-databind:2.16.0

Then, run it as follows:

from JSON to Java Map step-by-step guide


In this tutorial, you’ve learned how to utilize Jackson’s ObjectMapper to convert a JSON string into a Java Map. This capability is beneficial for parsing JSON data into a format that’s easily manipulable within Java applications.