In this chapter, we saw some examples on how to manipulate the XML and JSON formats in Scala and how to connect to other systems via web services. In the case of XML, we also covered how to generate SOAP bindings out of a WSDL description as well as Scala classes to encapsulate the XML domain included in an XML schema. Web services in the Play Framework run asynchronously, which means that the caller is not waiting for the answer to come back before he continues to do other useful processing (such as serving other requests). In the next chapter, we are going to study this notion of asynchronous invocations more precisely. It is based on the concepts of Future and Promise that are also emerging in the Java world to deal with the execution of concurrent code. In particular, we will go through the Akka framework, an open source toolkit and runtime simplifying the construction of concurrent applications. Designed and written in Scala, Akka contains both Scala and Java APIs and is the...