docs: service locator and service stub diagrams

service-locator/README.md

@@ -33,6 +33,10 @@ Wikipedia says
 
 > The service locator pattern is a design pattern used in software development to encapsulate the processes involved in obtaining a service with a strong abstraction layer. This pattern uses a central registry known as the "service locator", which on request returns the information necessary to perform a certain task. Proponents of the pattern say the approach simplifies component-based applications where all dependencies are cleanly listed at the beginning of the whole application design, consequently making traditional dependency injection a more complex way of connecting objects. Critics of the pattern argue that it is an antipattern which obscures dependencies and makes software harder to test.
 
+Sequence diagram
+
+![Service Locator sequence diagram](./etc/service-locator-sequence-diagram.png)
+
 ## Programmatic Example of Service Locator Pattern in Java
 
 The Service Locator design pattern is used to abstract the processes involved in obtaining a service. It uses a central registry, the "service locator", which returns the necessary information to perform a task upon request. This Java design pattern is particularly useful in enterprise Java applications where services need centralized management.