Java API to Document AI - Proxy-Configuration

Google Cloud Build with AI AI Solutions
1

Hello,
my question is: How can I configure a Proxy for the Document-AI-Client by using Java-Code, not using Java-System-Property.

I am using this code for creating the Document-AI-Client.

DocumentProcessorServiceClient client;
String endpoint = "eu-documentai.googleapis.com:443";
try (InputStream jsonCredentialsFile = getPropertyInputStream(getClass(), "jsonCredentialsFile")) {
   GoogleCredentials credentials = GoogleCredentials.fromStream(jsonCredentialsFile)
     .createScoped(Lists.newArrayList("https://www.googleapis.com/auth/cloud-platform"));
   client = DocumentProcessorServiceClient.create(DocumentProcessorServiceSettings.newBuilder()
     .setEndpoint(endpoint)
     .setCredentialsProvider(FixedCredentialsProvider.create(credentials))
     .build()
   );
}
ProcessRequest request = ProcessRequest.newBuilder()
.setName(processorName)
.setSkipHumanReview(true)
.setFieldMask(FieldMask.newBuilder().build())
.setRawDocument(rawDocument)
.build();

// Process document
ProcessResponse result = client.processDocument(request);
Document documentResponse = result.getDocument();

If I use Java-System-Property "-D http.proxy … " Everything works fine.

But I have to access other Systems in the LAN by using e.g. Apache httpclient and other clients.
The global Java-System-Property interferes with the other kinds of clients, because all of them are using the Java-System-Property. I cannot Mix “Proxy” and “no Proxy”.

Of cause the other clients can be separately configured to use a Proxy or not.
And the Document-AI-Client can use the Java-System-Property.
But it would be much better if I could configure the Proxy for the Document-AI-Client alike.

2

I found the solution here
https://stackoverflow.com/questions/68300018/how-to-configure-proxy-credentials-for-google-pub-sub-grpc-calls

Proxying is well documented here
https://github.com/googleapis/google-cloud-java#configuring-a-proxy
The above Dokument seem to be the actual basis for google-cloud-clients. But not for all Google-APIs!