adam bien's blog

import javax.enterprise.concurrent.ManagedExecutorService;
public class EventSource {

    
    @Resource
    ManagedExecutorService threadPool;
(...)
}

In pure MicroProfile environments these API is not available but can be replaced with ManagedExecutor from MicroProfile Context Propagation:

import org.eclipse.microprofile.context.ManagedExecutor;
public class EventSource {

    @Inject
    ManagedExecutor executor;
}

Both injected instances are inheriting from ExecutorService. Migration from javax.enterprise.concurrent.ManagedExecutorService to org.eclipse.microprofile.context.ManagedExecutor should be matter of replacing @Resource with @Inject, renaming the injected classes and fixing the imports.