Please suggest JMeter plugin or debugger so that we are able to see runtime error when we are doing executions
Here are my thoughts about your problem:
- If there is an error occurs in application under test then how visible it would be from the outside depends on how the application exposes errors to the outer world. The normal way to do that is to log the errors to a file or to some logging service that in turn decides how to preserve the messages.
- When your JMeter executes a request, application might handle that single request with multiple threads, that processing might be asynchronous so there might not be the way to associate the error with the particular request.
- If there is a way, then the most simple way to monitor runtime error is when your application returns error messages within response body, however this is not always the case.
So in my opinion the most simple way to debug your tests would be isolating the part of your test you'd like to debug, executing that part and analyzing the application log. Likely the log messages contain the time markers that would let you associate what happened in the application when your JMeter test was executing.