As we saw earlier, when the test script asks for a test platform with a desired capability, the hub will reject the request if it doesn't find a suitable node with the desired capability.

Altering the value for the throwOnCapabilityNotPresent parameter can alter this behavior. By default, it is set to true, which means the hub will reject the request if it doesn't find a suitable node with that capability. But setting this parameter to false will queue the request, and the hub will wait until a node with that capability is added to the grid. The command that has to be invoked is as follows:

java -jar selenium-server-standalone-3.12.0.jar -role hub -port 1111 -throwOnCapabilityNotPresent false

Now the hub will not reject the request, but will place the request in a queue and wait until the requested platform is available.