swagger-codegen Java client throws PROTOCOL_ERROR when running on Android

[Cloudmersive]

Description

When running Java client on Android, it throws PROTOCOL_ERROR - I think it has something to do with Java client using an old version of OkHttp that has HTTP2.0 bugs

Swagger-codegen version

2.3.1

Swagger declaration file content or url

https://api.cloudmersive.com/convert/docs/v1/swagger

Command line used for generation

java -jar swagger-codegen-cli.jar generate -i https://api.cloudmersive.com/convert/docs/v1/swagger -l java --api-package com.cloudmersive.client --model-package com.cloudmersive.client.model --invoker-package com.cloudmersive.client.invoker --group-id com.cloudmersive --artifact-id cloudmersive-java-api-client --artifact-version 1.1.9 -o .

Steps to reproduce

Generate the client using above command

Create a test project in Android Studio

Immediately see the protocol_error:

com.cloudmersive.client.invoker.ApiException: java.io.IOException: stream was reset: PROTOCOL_ERROR

We also tried generating the client with the other library templates but those don't actually compile - pretty frustrating.

Related issues/PRs

square/okhttp#1844

Suggest a fix/enhancement

Change the Java client to use OK HTTP 3.11.0 instead of old 2.75.0 version

[Cloudmersive]

PS - This works fine on desktop Java which is why we think it is the OK HTTP problem

[HugoMario]

thanks for filing this @Cloudmersive, is it possible you propose a PR? i would like to address this, but i'm really busy with other codegen issues.

[Cloudmersive]

Currently we were able to solve this by just turning off HTTP/2 support in OKHttp, so confirmed it is the HTTP/2 bug in this version of OkHttp. Can see if we can submit a PR.