The idea of the ContextPropagator is that it’s called before and after your workflow client, workflow, and activity code is executed so that you can grab some contextual information and pass it along. The way that we use it is to grab some values from the
org.slf4j.MDC in your workflow client thread and make sure that those values are populated in the MDC before your workflow code or activity code start.
This is a sample context propagator in the unit test: https://github.com/temporalio/sdk-java/blob/f0bbf84c496454d9909caefe6ca2784f76b8e592/temporal-sdk/src/test/java/io/temporal/internal/testing/WorkflowTestingTest.java#L878
getCurrentContext() method is called before a workflow/child workflow/activity is started to grab the context from your code, then before your workflow/child workflow/activity starts,
setCurrentContext() is called to set up the context in the child thread.
Does that help? You can define what “context” means, but those methods give you hooks to get/set it on your code’s threads.