Java to JSON Converter

Generate sample JSON from Java class definitions with annotation-aware key mapping.

PrettyUse annotationsInclude nullsIndent

Java Input

JSON Output

7 fields

{
  "user_id": 0,
  "name": "",
  "email": "",
  "active": false,
  "balance": 0,
  "roles": [],
  "address": {}
}

How to Use

Paste your Java class code or upload a .java file.
Configure output options (pretty print, annotations, nulls).
The sample JSON is generated instantly.
Copy or download the result.

Frequently Asked Questions

How does Java to JSON conversion work?

The tool parses your Java class fields and their types, then generates a sample JSON object with default values for each type. String becomes "", int becomes 0, boolean becomes false, and so on.

Does it support Jackson and Gson annotations?

Yes. When "Use annotations" is enabled, @JsonProperty("key") and @SerializedName("key") are used as the JSON key names instead of field names.

What Java types are supported?

String, int/Integer, long/Long, double/Double, float/Float, boolean/Boolean, BigDecimal, Date, LocalDate, LocalDateTime, List, Map, and nested object types.

Is my code secure?

Yes. Everything runs in your browser. Your Java code is never sent to any server.

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