Clojure: High Performance JVM Programming

Proxy and reify

There are situations when you are interacting with Java libraries, where you must send an instance of a specific Java class to some method; writing a class isn't the best option, you should rather create an instance that conforms to a contract expected by some framework on the fly. We have two options to do this:

• Proxy: It allows you to implement a Java interface or extend from some super class. In reality, it creates a new object that calls your Clojure functions when needed
• Reify: Reify allows you to implement interfaces and Clojure protocols (we will see them later). It is not capable of extending classes. It is a better performant than the proxy and should be used whenever possible.

Let's look at a minimal example:

(import '(javax.swing ...