I think it is the best way to load and discard lots of dynamically-loaded
and in fact dynamically-generated classes.
Joshua
On Wed, Mar 4, 2009 at 5:21 PM, Hendrik <geheimm...@gmail.com> wrote:
>
> Hi,
>
> I got a question: Clojure seems to create poopillions of
> DynamicClassLoader instances. Why does it do that? Could I try
> patching it so that it creates less of them? I need this cause I ran
> into trouble working with JNI.
>
> I looked at the Clojure source rev 1323. I'm no expert, this is my
> first look at the sources, but the following struck me as hack-ish:
> (from Compiler.java, shortened slightly)
>
> public static Object eval(Object form) throws Exception{
> if(true)//!LOADER.isBound())
> makeClassLoader();
>
> To me, that looks like for evaluating _every form_, a new classloader
> gets created. Isn't that a bit much? Also, it looks "temporary" that
> the if() has its condition commented out and replaced with
> true ... :-/ So Clojure's behavior seems to have been different at
> some point in the past.
>
> Thanks a bunch for your opinions.
>
> Cheers
> Hendrik
>
>
>
> Details:
>
> I'm asking because I was loading a native library through JNI. The
> rule here (apparently) is that you can load a library through only one
> classloader, not the same library through several loaders.
>
> For example, this program fails:
>
> (System/load "/home/hk/inotify-java-0.1/build/native/libinotify-
> java.so")
> (System/load "/home/hk/inotify-java-0.1/build/native/libinotify-
> java.so")
>
> I feel that the program should work. Apparently Clojure creates new
> classloaders between line 1 and 2. An equivalent Java program does
> work (the first System.load() loads the library, the second sees the
> library is already loaded and does nothing).
>
> This is the exact error message:
>
> $ cat t3.clj
> (System/load "/home/hk/inotify-java-0.1/build/native/libinotify-
> java.so")
> (System/load "/home/hk/inotify-java-0.1/build/native/libinotify-
> java.so")
> (println "42")
>
> $ java -jar /home/hk/clojure-svn-2/clojure.jar t3.clj
> java.lang.UnsatisfiedLinkError: Native Library /home/hk/inotify-
> java-0.1/build/native/libinotify-java.so already loaded in another
> classloader (t3.clj:0)
> at clojure.lang.Compiler.eval(Compiler.java:4533)
> at clojure.lang.Compiler.load(Compiler.java:4846)
> at clojure.lang.Compiler.loadFile(Compiler.java:4813)
> at clojure.main$load_script__5685.invoke(main.clj:206)
> at clojure.main$script_opt__5716.invoke(main.clj:258)
> at clojure.main$main__5740$fn__5742.invoke(main.clj:333)
> at clojure.main$main__5740.doInvoke(main.clj:328)
> at clojure.lang.RestFn.invoke(RestFn.java:413)
> at clojure.lang.Var.invoke(Var.java:346)
> at clojure.lang.AFn.applyToHelper(AFn.java:173)
> at clojure.lang.Var.applyTo(Var.java:463)
> at clojure.main.main(main.java:39)
> Caused by: java.lang.UnsatisfiedLinkError: Native Library /home/hk/
> inotify-java-0.1/build/native/libinotify-java.so already loaded in
> another classloader
> at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1743)
> at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1674)
> at java.lang.Runtime.load0(Runtime.java:770)
> at java.lang.System.load(System.java:1005)
> at user$eval__4.invoke(t3.clj:2)
> at clojure.lang.Compiler.eval(Compiler.java:4522)
> ... 11 more
>
> $
>
>
> >
>
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