clojure.core/*use-context-classloader*

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Type: var Added: Clojure unknown Examples: 2 Runnable: 1

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Examples

by reborg on 2021-04-05 . May have evaluation errors. ▶

;; *use-context-classloader* is always bound to true regarldess of any ;; outer binding setting and thus ignored. ;; The initial idea was to have a way to tell Clojure to ignore ;; the context classloader (supposedly set by external libs or frameworks) ;; in some pretty specific OSGi scenarios. Original context can be found at: ;; https://groups.google.com/g/clojure/c/aXsFBdowdsA/m/1Ez894XuT30J and ;; additional use cases https://clojure.atlassian.net/browse/CLJ-2593 (import '[clojure.lang DynamicClassLoader]) (def custom-classloader (DynamicClassLoader.)) (.setContextClassLoader (Thread/currentThread) custom-classloader) (identical? (.. (fn []) getClass getClassLoader getParent) custom-classloader) ;; true ;; This should return false and use some other class loader (binding [*use-context-classloader* false] (identical? (.. (fn []) getClass getClassLoader getParent) custom-classloader)) ;; true ;; WARNING: If the examples above don't seem to return the expected results, ;; be aware that tools like Leiningen[https://leiningen.org/] or ;; nRepl[https://github.com/nrepl/nrepl] alter the context class loader. ;; Please use a vanilla REPL like ;; clojure.deps[https://clojure.org/guides/getting_started] instead.

by KingMob on 2022-06-21 ▶

;; The above example has one minor caveat to be aware of for those who need ;; to work with classloaders. *use-context-classloader* is not technically ;; ignored, because RT/baseLoader will use it. But it's usually overridden ;; by RT/makeClassLoader, which pushes a binding that sets it to true every ;; time it's called. And RT/makeClassLoader is called every time eval or ;; compile1 is called and in some versions of load(), so it happens a lot.

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