JSON to Java Converter
Convert JSON to Java POJO classes for Java development
JSON Input
Java Output
What Is JSON to Java?
Java uses POJOs (Plain Old Java Objects) for structured data. When you consume JSON with Jackson or Gson, you need matching Java classes with the right field names and types. The JSON specification defines objects, arrays, strings, numbers, and booleans—but Java needs explicit class definitions for each nested object. Writing those by hand is tedious when the JSON is large or the API changes frequently.
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, the JSON Path tool works well alongside this.
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
Lombok or manual getters/setters?
Lombok generates getters, setters, constructors, and equals/hashCode at compile time. It significantly reduces boilerplate. Requires Lombok on the classpath and annotation processing enabled. Without it, you get manual getters and setters.
What about Jackson vs Gson?
Both work with the generated POJOs. Jackson uses @JsonProperty for custom key names; Gson uses @SerializedName. The generator typically produces Jackson-compatible output. Add Gson annotations manually if needed.
Is my data sent anywhere?
No. Generation runs entirely in your browser using JavaScript. No data is sent to any server. You can confirm this by opening your browser's Network tab while using the tool.
Nullable types?
Enable Nullable Types for Optional<T> or @Nullable on optional JSON fields. This helps when a field can be null or missing in the API response.
Record classes?
Java 16+ records are immutable and concise. This tool may generate regular classes. For records, you might need to edit the output or use a different generator that supports records.
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.