# Runtime exception when requiring datomic client

**URL:** <https://forum.datomic.com/t/runtime-exception-when-requiring-datomic-client/301>\
**Category:** Troubleshooting\
**Created:** [January 28, 2018, 6:30pm UTC](https://forum.datomic.com/t/runtime-exception-when-requiring-datomic-client/301 "2018-01-28T18:30:55Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![james.lane.conkling](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.datomic.com/james.lane.conkling/32/142_2.png) [@james.lane.conkling](https://forum.datomic.com/u/james.lane.conkling)\
**Post date:** [January 28, 2018, 6:30pm UTC](https://forum.datomic.com/t/runtime-exception-when-requiring-datomic-client/301/1 "2018-01-28T18:30:55Z")

</div>

Working through the [Getting Started](https://docs.datomic.com/on-prem/getting-started/connect-to-a-database.html) tutorial, and getting a runtime error whenever I require the client library.

```
; project.clj
(defproject datomic-client "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"}
  :dependencies [[org.clojure/clojure "1.8.0"]
                 [com.datomic/client-pro "0.8.14"]]
  :main ^:skip-aot datomic-client.core
  :target-path "target/%s"
  :profiles {:uberjar {:aot :all}})

; src/datomic_client/core.clj
(ns datomic-client.core
  (require [datomic.client.api :as d])
  (:gen-class))

 (defn -main
  "I don't do a whole lot ... yet."
   [& args]
   (println d))

```

Which throws the following error:

```
CompilerException java.lang.RuntimeException: Unable to resolve symbol: halt-when in this context, compiling:(datomic/client/api.clj:57:11)

```

Using java **1.8.0\_161**.

Totally new to Datomic, and new-ish to Clojure, so might be missing something obvious here. But searching for solutions 1.5 days hasn’t yielded anything yet.

---

<div class="post-metadata">

**Author:** ![james.lane.conkling](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.datomic.com/james.lane.conkling/32/142_2.png) [@james.lane.conkling](https://forum.datomic.com/u/james.lane.conkling)\
**Post date:** [January 28, 2018, 11:29pm UTC](https://forum.datomic.com/t/runtime-exception-when-requiring-datomic-client/301/2 "2018-01-28T23:29:28Z")

</div>

Looks like `halt-when` was introduced in Clojure 1.9. Upgraded and everything works fine.

---

<div class="post-metadata">

**Author:** ![marshall](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.datomic.com/marshall/32/48_2.png) [@marshall](https://forum.datomic.com/u/marshall)\
**Post date:** [January 29, 2018, 5:00pm UTC](https://forum.datomic.com/t/runtime-exception-when-requiring-datomic-client/301/3 "2018-01-29T17:00:58Z")

</div>

Glad you got it sorted.  
Yes, the latest Client requires Clojure 1.9

-M