Getting Clojure

… And Back to Clojure

To see how we can get at the wonders of Java from Clojure, let’s reach for every programmer’s favorite abstraction, the file. Java comes packaged with a handy class for representing files, namely java.io.File. According to the documentation for java.io.File, we can create an instance by passing in a string, the path to the file. To create a new instance of a Java class using Clojure’s interoperation facilities—interop for short—we use the classname with a dot on the end in the lead-off spot in the expression:

interop/examples.clj

(def authors (java.io.File. "authors.txt"))

The preceding code will create a new instance of java.io.File, calling the constructor along the way, and return that instance—which represents ...