[BUG] ClassCastException occurs in extractAndWrapCause method of AwsSdk2Transport when ExecutionException's cause is not an Exception or Error

[wonthechan]

What is the bug?

In the extractAndWrapCause method of AwsSdk2Transport, when handling an ExecutionException, the code assumes that executionException.getCause() is always an Exception or Error.

However, getCause() can return a Throwable that is neither an Exception nor an Error.
If the cause is another type of Throwable (e.g., a custom subclass that is neither Error nor Exception), the following line will cause a ClassCastException:

exception = (Exception)t;

This results in the loss of the original exception details.

How can one reproduce the bug?

This issue can be reproduced when using NettyNioAsyncHttpClient as the SdkAsyncHttpClient with a low connectionAcquisitionTimeout value.

Steps to reproduce:
1. Set up an OpenSearchClient using AwsSdk2Transport with NettyNioAsyncHttpClient.
2. Configure the client with a very low connectionAcquisitionTimeout, such as 1 millisecond.
3. Attempt to make a request to OpenSearch
4. When a connectionAcquisitionTimeout occurs, it triggers an ExecutionException.
5. The extractAndWrapCause method processes the exception, but if the cause is a Throwable that is neither an Error nor an Exception, a ClassCastException is thrown.

This results in the loss of the original exception context, making it difficult to diagnose the actual timeout issue.

What is the expected behavior?

When a connectionAcquisitionTimeout occurs, the exception should be correctly propagated without causing a ClassCastException.
• If the cause of ExecutionException is an Error, it should be rethrown (which is already handled correctly in the current implementation).
• If the cause is an Exception, it should be processed as intended.
• If the cause is a Throwable that is neither an Error nor an Exception, the code should not attempt to cast it to an Exception, as this leads to a ClassCastException. Instead, it should be wrapped in a more appropriate exception (e.g., RuntimeException).

What is your host/environment?

Mac OS Sonoma 14.6
opensearch-java:2.22.0
netty-nio-client:2.30.37
org.springframework.boot 3.2.7

Do you have any screenshots?

N/A

If possible, I would be happy to create a PR to fix this issue.

[Xtansia]

@wonthechan Thanks for reporting this, if you're interested in creating a fix for this it would be greatly welcomed.