String getTypeHeader() throws JwtInvalidException {
    if (!typeHeader.isPresent()) {
      throw new JwtInvalidException("type header is not set");
    }
    return typeHeader.get();
  }
Adds a custom claim encoded in a JSON {@code String} to the JWT.
java_src/src/main/java/com/google/crypto/tink/jwt/RawJwt.java