[Quinn-With-Two-Ns]

What changed?

• Auto-configure a primary temporalActivityClient and namespace/alias-prefixed activity clients, following the existing ScheduleClient wiring and capabilities.
• Apply namespace data converters, root ActivityClientInterceptor beans, and ordered TemporalOptionsCustomizer<ActivityClientOptions.Builder> beans, including the existing namespace-specific naming convention.
• Add wiring and options customization tests, documentation, and a changelog entry.

Why?

Applications should be able to inject an ActivityClient without manually reproducing the Spring namespace, converter, and interceptor configuration. Invocation-specific task queues and timeouts remain in StartActivityOptions.

Fixes #3146.

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Note

Medium Risk
Expands Spring bean surface and constructor signatures in autoconfigure templates; misconfigured customizers or duplicate beans could affect runtime client behavior, but changes mirror existing ScheduleClient patterns.

Overview
Spring Boot now wires ActivityClient the same way it already does for ScheduleClient: a primary temporalActivityClient for the root namespace and <alias-or-namespace>ActivityClient beans for each configured non-root namespace.

ClientTemplate lazily builds clients from shared service stubs (including the test-server path). WorkflowClientOptionsTemplate.createActivityClientOptions() sets namespace and data converter, prepends OpenTracing when a Tracer is present, applies root ActivityClientInterceptor beans only on the root client, and runs ordered TemporalOptionsCustomizer<ActivityClientOptions.Builder> beans (namespace-specific names like assignActivityClientCustomizer for non-root). Non-root namespaces register their activity client via NonRootBeanPostProcessor.

Deprecated overloads on ClientTemplate, NonRootNamespaceTemplate, and WorkflowClientOptionsTemplate that omitted activity-client parameters were removed. README, changelog, and tests cover injection, customizers, multi-namespace beans, and interceptor ordering.

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[panakantinandu]

Hi Quinn, thanks for working on the ActivityClient Spring Boot integration!

While reviewing #3157, I noticed that createActivityClientOptions() doesn't register OpenTracingActivityClientInterceptor when a Tracer bean is available, whereas the existing workflow client configuration handles tracing.

I reproduced this locally on the PR branch by adding a regression test. Both test-server and non-test-server configurations failed because the activity client was missing the tracing interceptor.

I then tested a small fix that registers OpenTracingActivityClientInterceptor before user-provided interceptors, following the workflow client pattern.

The targeted tests now pass:

• ActivityClientAutoConfigurationTest: 6/6
• ClientOnlyTest: 3/3
• MultiNamespaceTest: 1/1
• AutoConfigOrderingTest: 1 passed, 1 skipped

The regression test verifies interceptor registration and ordering across root and non-root namespaces. I haven't verified actual span generation end to end.

Would you be open to a small follow-up contribution with the fix and regression tests, or would you prefer to incorporate it into your existing PR?

Happy to help either way!