code: public String generate(final Map<String, Object> claims) {
          // claims builder
          final JWTClaimsSet.Builder builder = new JWTClaimsSet.Builder();
  
          // add claims
          for (final Map.Entry<String, Object> entry : claims.entrySet()) {
              builder.claim(entry.getKey(), entry.getValue());
          }
          if (this.expirationTime != null) {
              builder.expirationTime(this.expirationTime);
          }
          return internalGenerate(builder.build());
      }
docs: Generate a JWT from a map of claims.
  
  @param claims the map of claims
  @return the created JWT