code: public static String dsnLookup() {
          String dsn = Lookup.lookup("dsn");
  
          if (Util.isNullOrEmpty(dsn)) {
              // check if the user accidentally set "dns" instead of "dsn"
              dsn = Lookup.lookup("dns");
          }
  
          if (Util.isNullOrEmpty(dsn)) {
              logger.warn("*** Couldn't find a suitable DSN, Sentry operations will do nothing!"
                  + " See documentation: https://docs.sentry.io/clients/java/ ***");
              dsn = DEFAULT_DSN;
          }
  
          return dsn;
      }
docs: Looks for a DSN configuration within JNDI, the System environment or Java properties.
  
  @return a DSN configuration or null if nothing could be found.