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What should be the Regular expression if I want to extract the value for access token, So that i can use it in Path of other Http request ie like access_token=93ee29b4-74dc-4uu7-8e10-6eac6845511b from below http response.

{
   "access_token":"93ee2tum-1234-56789-8e10-6eac684551tum",
   "token_type":"Bearer",
   "expires_in":3600,
   "scope":"test"
}

I have given regular expression as

"access_token":"([^"]+)"

And also where can i check the value of regular expression I am getting

You can test your Regular Expressions using View Results Tree listener in RegExp Tester mode like:

Also you can use Debug Sampler to see the associated JMeter Variables. See How to Debug your Apache JMeter Script article for details.

Starting from JMeter 3.0 it's more handy to use JSON Path PostProcessor, in that case the relevant JSON Path Expression would be as simple as:

$.access_token