Could not locate clojure/data/xml__init.class in a luminus project

In my luminus project I've added this:

[org.clojure/data.zip "0.1.2"]

to the list of dependencies but this throws an exception still:

(ns myapp.rss
  (:use [clojure.data.xml :as xml :only [emit]]))

which is:

Could not locate clojure/data/xml__init.class or clojure/data/xml.clj on classpath

Solution

here is a working example to compare with:

project.clj:

(defproject hello "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :main hello.core
  :dependencies [[org.clojure/clojure "1.7.0"]                 
                 [org.clojure/data.xml "0.0.8"]
                 [org.clojure/data.zip "0.1.2"]
                 [clj-http "2.2.0"]])

from core.clj:

(ns hello.core
  (:require [clj-http.client :as http-client]
            [clojure.zip :as zip]
            [clojure.xml :as xml]
            [clojure.data.xml :as xml-data :refer [emit]]
            [clojure.data.zip.xml :as xml-z]))

(use ... :only) has been deprecated by the require :refer pattern.

And here are some common things to check:

you have actually fetched the dependencies since adding them to the project.clj file
Try running lein deps from the command line to make sure fetching the dependencies worked
restart cider (if in emacs)
try from lein repl
if none of this works look in ~/.m2/repository and make sure the class files are there
run ps -ef (if in linux) to look at the command used to start java and make sure the classpath contains your dependency.