Generate JSON Schema using Jackson

JacksonJsonSchemaGenerator.java

public static void main(String[] args) throws Exception {
    ObjectMapper mapper = new ObjectMapper();
    JsonSchemaGenerator generator = new JsonSchemaGenerator(mapper);
    JsonSchema jsonSchema = generator.generateSchema(Subscription.class);

    StringWriter json = new StringWriter();
    mapper.configure(SerializationFeature.INDENT_OUTPUT, true);
    mapper.writeValue(json, jsonSchema);

    System.out.println(json.toString());
}
/*
    ** Needs the following dependency **
    <dependency>
        <groupId>com.fasterxml.jackson.module</groupId>
        <artifactId>jackson-module-jsonSchema</artifactId>
        <version>2.3.0</version>
    </dependency>
*/

You have to represent your input.json as a class with proper annotations (here is an example with a Subscription.class) and start this program.