JSON to Java Converter
Convert JSON to Java POJO classes for Java development
JSON Input
Java Output
What Is JSON to Java?
You're integrating a REST API in your Spring Boot or Android app, and the JSON response has 5 levels of nesting. Writing the Java POJO tree by hand — field by field, with getters, setters, and Jackson annotations — takes forever. This tool does it for you: paste the JSON in, get a complete set of Java classes out, ready to use with ObjectMapper.readValue() or Gson.fromJson().
This tool generates Java POJOs from your JSON. Set the package name and class name in the config panel. Enable Lombok for @Data or @Getter/@Setter to reduce boilerplate. Enable Nullable Types for Optional<T> or @Nullable on optional fields. The output works with ObjectMapper.readValue() (Jackson) or Gson.fromJson().
Conversion runs entirely in your browser. Your JSON is never sent to a server. You can confirm this by opening your browser's Network tab while using the tool.
When JSON to Java Helps
When building Spring Boot, Android, or any Java app that consumes REST APIs, you need typed POJOs. Use Jackson or Gson to parse. Paste a sample response here to generate matching classes.
How to Use This Tool
Paste or Upload JSON
Copy your JSON and paste it into the left editor. You can also click Upload to load a .json or .txt file from your computer. Use the Sample button to load example data. In the config panel, set the package name (e.g. com.example.model) and class name (e.g. User). Enable Lombok for @Data or @Getter/@Setter to reduce boilerplate.
Review the Generated Classes
The right panel shows the generated Java classes. Nested objects become inner or separate classes. Arrays become List<T>. Add @JsonProperty (Jackson) or @SerializedName (Gson) if JSON keys differ from Java field names. If your JSON has invalid syntax, fix it first using the JSON Formatter or JSON Validator.
Copy or Download
Use Copy to put the result on your clipboard, or Download to save it as a .java file. Paste into your project. You may need to add imports or adjust package names depending on your project structure.
JSON to Java Examples
Here is an example of generating Java POJO classes from a JSON object.
Example: Subscriber record
JSON input:
Generated Java output:
When JSON to Java Helps
Most developers need this when integrating with REST APIs. You send a request through Postman, Spring's RestTemplate, or HttpClient, and the response comes back as JSON. Pasting it here gives you typed POJOs you can use immediately with Jackson or Gson. For pulling out specific values from large responses, jq works well from the command line.
Microservices often exchange JSON. When a downstream service changes its API, you need updated DTOs. This tool lets you regenerate classes quickly. If you need to merge two JSON files first, there's a separate JSON Merge tool for that.
Database exports, config files, or event payloads are often JSON. Running them through here helps you understand the structure and generate Java classes for import scripts, message consumers, or persistence layers.
Frequently Asked Questions
How do I generate Java classes from JSON automatically?
Paste your JSON into this tool and it generates Java POJO classes instantly. Set the package name and class name in the config panel. Enable Lombok to skip writing getters/setters by hand. Copy the output and add it to your project.
Should I use Lombok or manual getters/setters?
Lombok is highly recommended for modern Java projects — it generates getters, setters, constructors, equals, and hashCode at compile time, cutting boilerplate massively. Just add the Lombok dependency and enable annotation processing. Without it, you get verbose but dependency-free classes.
Jackson or Gson — which should I use?
Both parse JSON into POJOs. Jackson is the default in Spring Boot and has richer features (mixins, custom serializers, tree model). Gson is simpler and good for Android. The generated classes work with both — use @JsonProperty (Jackson) or @SerializedName (Gson) for custom key names.
Is my data sent anywhere?
No. Everything runs in your browser — your JSON never leaves your machine. Safe to use with production API responses or internal data.
What about nullable and optional fields?
Enable Nullable Types to get Optional<T> or @Nullable on fields that can be null or absent in the API response. This makes it explicit in your model that a field might not always be present, helping avoid NullPointerExceptions.
Related Tools
For Java JSON libraries, see Jackson and Gson. For JSON, see the JSON specification and RFC 8259. For a general overview, see MDN JSON. For API testing, see Postman.