Is this possible to autorefresh kibana 4.1 dashboard

how to use grok filter for json data in logstash file .

Are you asking a Logstash or Kibana question?

Yes it is possible to autorefresh kibana 4.1 dashboard.

how is this possible ?

kibana.

Click the timepicker in the upper-right corner. Then click Auto-refresh. Select how often you would like it to refresh.