5.4. Summary

This chapter explored Clojure’s excellent support for interoperability with Java. This is an important feature, because it gives programmers instant access to thousands of libraries and frameworks. As you’ll see in later parts of the book, this is a huge advantage when it comes to building real-world systems in Clojure. You can write your application-specific code in Clojure and use well-tested, production-quality Java libraries for infrastructure-related requirements, for example, accessing HBase (an open-source implementation of Google’s BigTable) and using RabbitMQ (an extremely fast messaging system).

This availability of a large number of well-tested, production-ready libraries and frameworks makes a huge difference to a new language such as Clojure. Apart from making all this functionality available to use from Clojure, the Java interop also makes it possible to write code that coexists with and leverages existing investments in Java systems. This allows Clojure to be brought into environments and organizations in an incremental fashion. Lastly, the elegance of the interop makes it easy to use Java code from within Clojure. All these factors contribute to making Clojure’s embrace of the Java platform a huge plus when considering the adoption of the language.