Java Class based on Enum fields

I'm dealing here with JWT and setting up custom fields.
All those custom fields are described in an Enum:

public enum JwtFields {
    userId,
    manyOtherCustomFieldsBellow,
    blaBlaBla
}

So whenever I create token instead of passing strings for the keys, I'm using an enum as it is faster and safer.

Claims claims = Jwts.claims().setSubject(userId);
claims.put(JwtFields.someCustomFieldFromEnum.name(), "someValue")

Now, once I check that the received token is valid and all necessary custom fields are present, I want to deserialise it to some TokenDecoded class and attach it to the request payload, so whenever I'm processing a request I will have all values and fields from the JWT token.

However, that deserialise class pretty much contains all fields from the enum, and if tomorrow I will add new fields to the enum, I'll have to also manually update my TokenDecoded class to include that new custom field too.

The question:
How can I make this TokenDecoded class to be based on the enum fields, so if I add a new field to the enum, it will be automatically present in TokenDecoded? Is there reflection involved? Or it could be achieved simpler?

Lombok provides a feature that works the other way 'round: If you define your fields in a class, you can annotate it with @FieldNameConstants(asEnum = true) to generate an enum based on the field names. Or, without the asEnum parameter, you'll get public static final Strings for your fields if you only need it as Strings.

You have several options:

• Use a Map instead of a class. Simplest solution but doesn't enforce typing or fields.
• Code generation: you can generate the class at compile time (e.g. JavaPoet).
• Byte code generation: you can generate byte code for the class at runtime (e.g. Javassist).
• Use Groovy metaprogramming features (or any other JVM-based language that support runtime data structure definition).

In my opinion code generation at compile time is best suited to your scenario.

Note that if you're using JWT you might want to look into a JWT library instead of reinventing the wheel.