public JavaLogger appendToFile(String logfile) {
      logger.setLevel(java.util.logging.Level.FINE);
      try {
        FileHandler handler = new FileHandler(logfile, true);
        handler.setFormatter(
            new SimpleFormatter() {
              @Override
              public String format(LogRecord record) {
                return String.format("%s%n", record.getMessage()); // NOPMD
              }
            });
        logger.addHandler(handler);
      } catch (IOException e) {
        throw new IllegalStateException("Could not add file handler.", e);
      }
      return this;
    }
Helper that configures java.util.logging to sanely log messages at FINE level without
additional formatting.
core/src/main/java/feign/Logger.java