Using AWS Java SDK 2.0 WebIdentityTokenFileCredentialsProvider gives SdkClientException

Question

This is cross posted on StackOverflow
https://stackoverflow.com/questions/75389388/using-aws-java-sdk-2-0-webidentitytokenfilecredentialsprovider-gives-sdkclientex

```
I have an application that already works using Kinesis. The application uses AWS Session Credentials but we are switching to using either AWS Session Credentials or Web Identity Token (software.amazon.awssdk.auth.credentials.WebIdentityTokenFileCredentialsProvider) depending on the deployment environment.

When I add in the code to use WebIdentityTokenFileCredentialsProvider I get the stacktrace below. I can't provide the code but rest assured I'm setting an HTTP client for Kinesis. But if you look at the stacktrace it shows that a default HTTP client is being configured via the Provider deep within the AWS SDK code. I have no influence over the Credentials Provider setting the HTTP client as the WebIdentityTokenFileCredentialsProvider doesn't give me a way to tell it that I don't need a default HTTP client being set.

I know one option is to create my own implementation of the WebIdentityTokenFileCredentialsProvider but I'd rather not do that.

Question: What else can I do to work around this?

Caused by: software.amazon.awssdk.core.exception.SdkClientException: Multiple HTTP implementations were found on the classpath. To avoid non-deterministic loading implementations, please explicitly provide an HTTP client via the client builders, set the software.amazon.awssdk.http.service.impl system property with the FQCN of the HTTP service to use as the default, or remove all but one HTTP implementation from the classpath
    at software.amazon.awssdk.core.exception.SdkClientException$BuilderImpl.build(SdkClientException.java:102)
    at software.amazon.awssdk.core.internal.http.loader.ClasspathSdkHttpServiceProvider.loadService(ClasspathSdkHttpServiceProvider.java:62)
    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
    at java.base/java.util.Spliterators$ArraySpliterator.tryAdvance(Spliterators.java:1002)
    at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:129)
    at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:527)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:513)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
    at java.base/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
    at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.base/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:647)
    at software.amazon.awssdk.core.internal.http.loader.SdkHttpServiceProviderChain.loadService(SdkHttpServiceProviderChain.java:44)
    at software.amazon.awssdk.core.internal.http.loader.CachingSdkHttpServiceProvider.loadService(CachingSdkHttpServiceProvider.java:46)
    at software.amazon.awssdk.core.internal.http.loader.DefaultSdkHttpClientBuilder.buildWithDefaults(DefaultSdkHttpClientBuilder.java:40)
    at software.amazon.awssdk.core.client.builder.SdkDefaultClientBuilder.lambda$resolveSyncHttpClient$7(SdkDefaultClientBuilder.java:343)
    at java.base/java.util.Optional.orElseGet(Optional.java:364)
    at software.amazon.awssdk.core.client.builder.SdkDefaultClientBuilder.resolveSyncHttpClient(SdkDefaultClientBuilder.java:343)
    at software.amazon.awssdk.core.client.builder.SdkDefaultClientBuilder.finalizeSyncConfiguration(SdkDefaultClientBuilder.java:282)
    at software.amazon.awssdk.core.client.builder.SdkDefaultClientBuilder.syncClientConfiguration(SdkDefaultClientBuilder.java:178)
    at software.amazon.awssdk.services.sts.DefaultStsClientBuilder.buildClient(DefaultStsClientBuilder.java:27)
    at software.amazon.awssdk.services.sts.DefaultStsClientBuilder.buildClient(DefaultStsClientBuilder.java:22)
    at software.amazon.awssdk.core.client.builder.SdkDefaultClientBuilder.build(SdkDefaultClientBuilder.java:145)
    at software.amazon.awssdk.services.sts.internal.StsWebIdentityCredentialsProviderFactory$StsWebIdentityCredentialsProvider.(StsWebIdentityCredentialsProviderFactory.java:71)
    at software.amazon.awssdk.services.sts.internal.StsWebIdentityCredentialsProviderFactory$StsWebIdentityCredentialsProvider.(StsWebIdentityCredentialsProviderFactory.java:55)
    at software.amazon.awssdk.services.sts.internal.StsWebIdentityCredentialsProviderFactory.create(StsWebIdentityCredentialsProviderFactory.java:47)
    at software.amazon.awssdk.auth.credentials.WebIdentityTokenFileCredentialsProvider.(WebIdentityTokenFileCredentialsProvider.java:86)
    at software.amazon.awssdk.auth.credentials.WebIdentityTokenFileCredentialsProvider.(WebIdentityTokenFileCredentialsProvider.java:46)
    at software.amazon.awssdk.auth.credentials.WebIdentityTokenFileCredentialsProvider$BuilderImpl.build(WebIdentityTokenFileCredentialsProvider.java:200)

```

Accepted Answer

I figured out the issue. I had added an exclusion for the dependency for UrlConnectionHttpClient in the AWS dependencies use but it wasn't being honored by Gradle. The reason being that there was another internal library that we have that also brings in AWS dependencies. Gradle let the internal dependency override the explicit exclusion I had added. So when I added the exclusion in that library for the dependency that contains UrlConnectionHttpClient it finally excluded it.

For the record we manually set the HttpClient but what happens with WebIdentityTokenFileCredentialsProvider is it's looking at the classpath and if it finds more than one it throws the exception noted above.

For the record we manually set the HttpClient but what happens with `WebIdentityTokenFileCredentialsProvider` is it's looking at the classpath and if it finds more than one it throws the exception noted above.

Answer

Hello,

In regards to the error -

```
SdkClientException: Multiple HTTP implementations were found on the classpath
```

This usually means that you have more than one HTTP client in your classpath (ApacheHttpClient and UrlConnectionHttpClient for example), the SDK was not able to choose one by default. You need to explicitly set which http client you want to use in the client definition.

If you still have any Java SDK issues, please feel free to post them here - 
> https://github.com/aws/aws-sdk-java/issues

References:
[1] https://aws.amazon.com/blogs/developer/introducing-aws-common-runtime-http-client-in-the-aws-sdk-for-java-2-x/

Using AWS Java SDK 2.0 WebIdentityTokenFileCredentialsProvider gives SdkClientException

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