I am trying to implement a Java interface that is required by a legacy runtime I am using and instantiate an instance of this implementation to pass it to the runtime. But when I run lein uberjar I see an exception, that the class cannot be found. Both namespaces are defined in the same leiningen project, so I would have expected, that they see each other as well as the classes generated by them.
(ns man.core
(:require (man.gateway))
(:import (man ManGate)
(eu.m2machine.gw GatewayComponentFactory))
(:gen-class))
(defn -main [& args]
(let [starter (.starter (GatewayComponentFactory/get))
gateway (ManGate.)]
(.startup starter gateway)))
This code tries to use a class implemented in the same project:
(ns man.gateway
(:import [eu.m2machine.gw.text GatewayIDFormatter])
(:gen-class
:name man.ManGate
:implements [eu.m2machine.gw.Gateway]
:prefix "gateway-"))
(defn gateway-startup [this])
(defn gateway-shutdown [this])
The two methods required by the interface only have stub implementations so far. They would get their code after I can compile the code. The interface is defined (in an artifact added as dependency):
package eu.m2machine.gw;
public interface Gateway {
void startup();
void shutdown();
}
The exception I get is:
Exception in thread "main" java.lang.ClassNotFoundException: man.ManGate, compiling:(man/core.clj:1:1)
at clojure.lang.Compiler.load(Compiler.java:7391)
at clojure.lang.RT.loadResourceScript(RT.java:372)
at clojure.lang.RT.loadResourceScript(RT.java:363)
at clojure.lang.RT.load(RT.java:453)
at clojure.lang.RT.load(RT.java:419)
at clojure.core$load$fn__5677.invoke(core.clj:5893)
at clojure.core$load.invokeStatic(core.clj:5892)
at clojure.core$load.doInvoke(core.clj:5876)
at clojure.lang.RestFn.invoke(RestFn.java:408)
at clojure.core$load_one.invokeStatic(core.clj:5697)
at clojure.core$load_one.invoke(core.clj:5692)
at clojure.core$load_lib$fn__5626.invoke(core.clj:5737)
at clojure.core$load_lib.invokeStatic(core.clj:5736)
at clojure.core$load_lib.doInvoke(core.clj:5717)
at clojure.lang.RestFn.applyTo(RestFn.java:142)
at clojure.core$apply.invokeStatic(core.clj:648)
at clojure.core$load_libs.invokeStatic(core.clj:5774)
at clojure.core$load_libs.doInvoke(core.clj:5758)
at clojure.lang.RestFn.applyTo(RestFn.java:137)
at clojure.core$apply.invokeStatic(core.clj:648)
at clojure.core$require.invokeStatic(core.clj:5796)
at clojure.core$require.doInvoke(core.clj:5796)
at clojure.lang.RestFn.invoke(RestFn.java:408)
at user$eval5$fn__7.invoke(form-init2162986879369932757.clj:1)
at user$eval5.invokeStatic(form-init2162986879369932757.clj:1)
at user$eval5.invoke(form-init2162986879369932757.clj:1)
at clojure.lang.Compiler.eval(Compiler.java:6927)
at clojure.lang.Compiler.eval(Compiler.java:6917)
at clojure.lang.Compiler.load(Compiler.java:7379)
at clojure.lang.Compiler.loadFile(Compiler.java:7317)
at clojure.main$load_script.invokeStatic(main.clj:275)
at clojure.main$init_opt.invokeStatic(main.clj:277)
at clojure.main$init_opt.invoke(main.clj:277)
at clojure.main$initialize.invokeStatic(main.clj:308)
at clojure.main$null_opt.invokeStatic(main.clj:342)
at clojure.main$null_opt.invoke(main.clj:339)
at clojure.main$main.invokeStatic(main.clj:421)
at clojure.main$main.doInvoke(main.clj:384)
at clojure.lang.RestFn.invoke(RestFn.java:421)
at clojure.lang.Var.invoke(Var.java:383)
at clojure.lang.AFn.applyToHelper(AFn.java:156)
at clojure.lang.Var.applyTo(Var.java:700)
at clojure.main.main(main.java:37)
Caused by: java.lang.ClassNotFoundException: man.ManGate
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at clojure.lang.DynamicClassLoader.findClass(DynamicClassLoader.java:69)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at clojure.lang.DynamicClassLoader.loadClass(DynamicClassLoader.java:77)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at clojure.lang.RT.classForName(RT.java:2168)
at clojure.lang.RT.classForNameNonLoading(RT.java:2181)
at man.core$eval20$loading__5569__auto____21.invoke(core.clj:1)
at man.core$eval20.invokeStatic(core.clj:1)
at man.core$eval20.invoke(core.clj:1)
at clojure.lang.Compiler.eval(Compiler.java:6927)
at clojure.lang.Compiler.eval(Compiler.java:6916)
at clojure.lang.Compiler.load(Compiler.java:7379)
... 42 more
I am wondering whether this could be a problem with the order in which the namespaces get compiled. Maybe leiningen is handling man.core before the class man.ManGate gets created!?
Edit:
I could solve my problem by changing the way I implement the interface:
(ns man.gateway
(:import [eu.m2machine.gw Gateway]))
(defn gateway []
(reify Gateway
(startup [this])
(shutdown [this]))
)
And in the namespace man.core I replaced the constructor call ManGate. with a call to man.gateway/gateway.
Still I would be interested to know why the solution above didn't work.
You class is defined in namespace man.gateway, but it's fully qualified class name is man.ManGate. Changing FQCN to man.gateway.ManGate in both core.clj and gateway.clj should solve the problem.