Logger.LoggerFactory.LoggerFactory.Log class and its methods.error log level.{} as the placeholder at error log level.LogLevel.info log level.{} as the placeholder at informational log level.RuntimeException at the error level and returns it to be thrown.RuntimeException at the warning level and returns it to be thrown.Throwable at the error level and returns it to be thrown.Throwable at the warning level and returns it to be thrown.verbose log level.{} as the placeholder at verbose log level.warning log level.{} as the placeholder at warning log level.