Azure Custom Vision Parameter this.client.endpoint() is required and cannot be null

I'm trying to get a basic Custom Vision image classifier working by following the tutorial in the Azure documentation found here: https://learn.microsoft.com/en-us/azure/cognitive-services/custom-vision-service/quickstarts/image-classification?pivots=programming-language-java

I have followed this tutorial word for word and have spent a couple days trying to work this out. The issue I am having is when running the code I am getting the following stack trace:

Parameter this.client.endpoint() is required and cannot be null.
java.lang.IllegalArgumentException: Parameter this.client.endpoint() is required and cannot be null.
    at com.microsoft.azure.cognitiveservices.vision.customvision.training.implementation.TrainingsImpl.createProjectWithServiceResponseAsync(TrainingsImpl.java:2313)
    at com.microsoft.azure.cognitiveservices.vision.customvision.training.implementation.TrainingsImpl$TrainingsCreateProjectParameters.execute(TrainingsImpl.java:2401)
    at com.microsoft.azure.cognitiveservices.vision.customvision.samples.CustomVisionSamples.ImageClassification_Sample(CustomVisionSamples.java:67)
    at com.microsoft.azure.cognitiveservices.vision.customvision.samples.CustomVisionSamples.runSample(CustomVisionSamples.java:46)
    at com.microsoft.azure.cognitiveservices.vision.customvision.samples.CustomVisionSamples.main(CustomVisionSamples.java:374)

The endpoint is defined here and passed as a parameter

final String Endpoint = System.getenv("AZURE_CUSTOMVISION_ENDPOINT");

            CustomVisionTrainingClient trainClient = CustomVisionTrainingManager.authenticate("https://{Endpoint}/customvision/v3.0/training/", CustomVisionTrainingClientKey).withEndpoint(Endpoint);
            CustomVisionPredictionClient predictClient = CustomVisionPredictionManager.authenticate("https://{Endpoint}/customvision/v3.0/prediction/", predictionApiKey).withEndpoint(Endpoint);

While the tutorial doesn't explicitly state to do so I have tried to set the system environment variable AZURE_CUSTOMVISION_ENDPOINT manually with PowerShell and it doesn't work with or without this set.

Am I missing something? Any help would be greatly appreciated!

Fixed my own issue. The environment variables had not set correctly and were null pointers. I replaced the System.getenv call to the string in plain text and this is working correctly.