code: public TimeZone getTimeZone() {
          if ( this.cronEx != null ) {
              return this.cronEx.getTimeZone();
          }
  
          if ( this.timeZone == null ) {
              this.timeZone = TimeZone.getDefault();
          }
          return this.timeZone;
      }
docs: <p>
  Returns the time zone for which the <code>cronExpression</code> of
  this <code>CronTrigger</code> will be resolved.
  </p>