Clojure's immutable and persistent data structures have been extracted as a Java library. You can find them at http://github.com/krukow/clj-ds. These data structures are not dependent on the Clojure runtime and hence can be used without the clojure.jar in your application's classpath. They have been generified to work smoothly with Java code.
Please make a note that working with these immutable data structures may not be idiomatic in Java.
The github page does not have a jar for download. You will have to checkout the source and build the jar yourself.
