I have a scenarios where User logs in to the Android App, scans some product's bar code and this way product get added to the cart.
I have recorded script for the same but how can JMeter script will work for multiple users for barcode?
Unlike functional tests, JMeter test works on the level of request between client and server, not between user and client. Barcode scanning is client side functionality, so you don't need to replicate barcode scanning itself as part of the performance test. But you need to know what happens after user scanned the barcode, which requests this operation generates, and if they are different from other operations. It could be that after scanning the barcode, application sends a request to "search" the product first, so you will need to replicate "search" request. Or it could be that barcode scanning does not create any additional requests to the server, in which case it doesn't need to be tested separately as part of the performance test.