Errata

Errata for Applied Akka Patterns

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The errata list is a list of errors and their corrections that were found after the product was released.

The following errata were submitted by our customers and have not yet been approved or disproved by the author or editor. They solely represent the opinion of the customer.

Color Key: Serious technical mistake Minor technical mistake Language or formatting error Typo Question Note Update

Version	Location	Description	Submitted by	Date submitted
Printed	Page 30 Ask	The import of akka.patterns.Ask should be added to the code sample, as people wanting to try it out will be wondering why the "?" is not working.	Dominik Dorn	Jun 17, 2017
Printed	Page 31 ActorSystem	It should be noted that creating multiple actor systems on one JVM is a anti-pattern. People else might start to create ActorSystems for different "modules" in their application.	Dominik Dorn	Jun 17, 2017
Printed	Page 31 ActorSystem	It should be noted that creating multiple actor systems on one JVM is a anti-pattern. People else might start to create ActorSystems for different "modules" in their application.	Dominik Dorn	Jun 17, 2017
Printed	Page 61 first paragraph talking about passing Promises	Passing around a Promise does not only violate the single-threaded illusion principle (by passing around a mutable data structure from another thread), it also breaks location transparency, as this will not work in a clustered / remote configuration of the actor system. While the first two approaches (using forward or a replyTo) reference are perfectly valid, this one is a real anti pattern (imho).	Dominik Dorn	Jun 19, 2017
Printed	Page 135 second code sample	it should be sender() ! msg instead of sender ! msg	Dominik Dorn	Jul 08, 2017