Is your feature request related to a problem? Please describe.
The SdkMeterProviderBuilder internally supports exemplars configuration via an ExemplarFilter. However, that's private since it's still marked as experimental and only configurable via the SdkMeterProviderUtil. That was done in #4272 since at that time the Spec for Exemplars was not stable yet (2022).

Describe the solution you'd like
Since the Exemplar Spec is now stable (https://opentelemetry.io/docs/specs/otel/metrics/sdk/#exemplar), it would be great to get stable APIs in the Java SDK as well. I'm not sure what it's missing before it can be declare stable, but I thought to open this issue to discuss that and keep track of the needed work.