I record the test script using Blaze Meter and run it on GUI of Jmeter, it works fine.

But the same script when running on Command Line gives Null Pointer. Why would this be the case?

My second question is: Can I manipulate the Same Recorded script with CSV DataSet Config in order to Login with Multiple Users?

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Here is Script In GUI in which I want to modify it with CSV DataSetConfig enter image description here

2 Answers 2

  • To sort out this null pointer I would recommend taking the next steps:

    1. Temporarily enable logging of requests and responses details by adding the next lines to user.properties file (located under "bin" folder of your JMeter installation)


      See Apache JMeter Properties Customization Guide to learn more about JMeter properties and ways of setting/overriding them.

    2. Run your test in command-line non-GUI mode

    3. Once test finishes open .jtl results file with View Results Tree listener and see requests and response details in it. Compare them with the ones you are getting in GUI mode. Additionally you may need to check jmeter.log file for any errors.
  • To parameterize your test, if you need to use a new userName and you have a file with usernames list you can amend your request body like:

    {"userName" : "${__StringFromFile(/path/to/file/with/usernames.csv,,,)}"}

    Above __StringFromFile() function returns new line from the given file each time being called so each JMeter thread (virtual user) will send a new username

  • did the changes in user.properties file still the same null pointer exception and while using "${__StringFromFile(E:\Filename.csv)}" stil reads no data from CSV Commented May 18, 2017 at 13:07
  • The changes are not intended to resolve the problem, they configure JMeter to store more information in the .jtl results file so you could figure out the cause.
    – Dmitri T
    Commented May 18, 2017 at 14:40
  • Nothing is getting recorded in my .jtl file because of the CSV file Error in the console says FileServer: Stored: path to the file\filename.csv and then it says java.lang.IllegalArgumentException: File Filename.csv must exist and be readable Commented May 19, 2017 at 5:36
  • It means that your csv file does not exist in the specified location, double check the path
    – Dmitri T
    Commented May 19, 2017 at 7:17

I have figured out why I was not able to run the recorded script.

By default, the ramp up period is zero. When I set some value in the file, save it, and run it in Non GUI mode, it works.

I still haven't figured out the CSV issue.

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