Clojure: NoClassDefFoundError with lein ring uberwar but not when I Compile with the REPL

Question

I am now experiencing a weird behavior with the clj-index library. I have been testing it for some time and everything was working perfectly and as expected when I was compiling my project with the REPL.

The issues started when I was trying to package my application in a WAR file using:

lein ring uberwar

This always worked for my application until I start using the clj-index library.

The error I am getting from Leiningen is:

Exception in thread "main" java.lang.NoClassDefFoundError: clj_index/core$find_L
 (wrong name: clj_index/core$find_l), compiling:(listener.clj:1:5)
        at clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3558)
        at clojure.lang.Compiler.compile1(Compiler.java:7226)
        at clojure.lang.Compiler.compile1(Compiler.java:7216)
        at clojure.lang.Compiler.compile1(Compiler.java:7216)
        at clojure.lang.Compiler.compile(Compiler.java:7292)
        at clojure.lang.RT.compile(RT.java:398)
        at clojure.lang.RT.load(RT.java:438)
        at clojure.lang.RT.load(RT.java:411)
        at clojure.core$load$fn__5066.invoke(core.clj:5641)
        at clojure.core$load.doInvoke(core.clj:5640)
        at clojure.lang.RestFn.invoke(RestFn.java:408)
        at clojure.core$load_one.invoke(core.clj:5446)
        at clojure.core$compile$fn__5071.invoke(core.clj:5652)
        at clojure.core$compile.invoke(core.clj:5651)
        at user$eval5.invoke(form-init8409087376793750134.clj:1)
        at clojure.lang.Compiler.eval(Compiler.java:6703)
        at clojure.lang.Compiler.eval(Compiler.java:6692)
        at clojure.lang.Compiler.eval(Compiler.java:6693)
        at clojure.lang.Compiler.load(Compiler.java:7130)
        at clojure.lang.Compiler.loadFile(Compiler.java:7086)
        at clojure.main$load_script.invoke(main.clj:274)
        at clojure.main$init_opt.invoke(main.clj:279)
        at clojure.main$initialize.invoke(main.clj:307)
        at clojure.main$null_opt.invoke(main.clj:342)
        at clojure.main$main.doInvoke(main.clj:420)
        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.NoClassDefFoundError: clj_index/core$find_L (wrong name: cl
j_index/core$find_l)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:14
2)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at clj_index.boyer_moore__init.load(Unknown Source)
        at clj_index.boyer_moore__init.<clinit>(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:340)
        at clojure.lang.RT.loadClassForName(RT.java:2093)
        at clojure.lang.RT.load(RT.java:430)
        at clojure.lang.RT.load(RT.java:411)
        at clojure.core$load$fn__5066.invoke(core.clj:5641)
        at clojure.core$load.doInvoke(core.clj:5640)
        at clojure.lang.RestFn.invoke(RestFn.java:408)
        at clj_index.core__init.load(Unknown Source)
        at clj_index.core__init.<clinit>(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:340)
        at clojure.lang.RT.loadClassForName(RT.java:2093)
        at clojure.lang.RT.load(RT.java:430)
        at clojure.lang.RT.load(RT.java:411)
        at clojure.core$load$fn__5066.invoke(core.clj:5641)
        at clojure.core$load.doInvoke(core.clj:5640)
        at clojure.lang.RestFn.invoke(RestFn.java:408)
        at clojure.core$load_one.invoke(core.clj:5446)
        at clojure.core$load_lib$fn__5015.invoke(core.clj:5486)
        at clojure.core$load_lib.doInvoke(core.clj:5485)
        at clojure.lang.RestFn.applyTo(RestFn.java:142)
        at clojure.core$apply.invoke(core.clj:626)
        at clojure.core$load_libs.doInvoke(core.clj:5524)
        at clojure.lang.RestFn.applyTo(RestFn.java:137)
        at clojure.core$apply.invoke(core.clj:626)
        at clojure.core$require.doInvoke(core.clj:5607)
        at clojure.lang.RestFn.invoke(RestFn.java:421)
        at umbel.tagger$loading__4958__auto__.invoke(tagger.clj:1)
        at umbel.tagger__init.load(Unknown Source)
        at umbel.tagger__init.<clinit>(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:340)
        at clojure.lang.RT.loadClassForName(RT.java:2093)
        at clojure.lang.RT.load(RT.java:430)
        at clojure.lang.RT.load(RT.java:411)
        at clojure.core$load$fn__5066.invoke(core.clj:5641)
        at clojure.core$load.doInvoke(core.clj:5640)
        at clojure.lang.RestFn.invoke(RestFn.java:408)
        at clojure.core$load_one.invoke(core.clj:5446)
        at clojure.core$load_lib$fn__5015.invoke(core.clj:5486)
        at clojure.core$load_lib.doInvoke(core.clj:5485)
        at clojure.lang.RestFn.applyTo(RestFn.java:142)
        at clojure.core$apply.invoke(core.clj:626)
        at clojure.core$load_libs.doInvoke(core.clj:5524)
        at clojure.lang.RestFn.applyTo(RestFn.java:137)
        at clojure.core$apply.invoke(core.clj:628)
        at clojure.core$use.doInvoke(core.clj:5618)
        at clojure.lang.RestFn.invoke(RestFn.java:619)
        at umbel.core$loading__4958__auto__.invoke(core.clj:1)
        at umbel.core__init.load(Unknown Source)
        at umbel.core__init.<clinit>(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:340)
        at clojure.lang.RT.loadClassForName(RT.java:2093)
        at clojure.lang.RT.load(RT.java:430)
        at clojure.lang.RT.load(RT.java:411)
        at clojure.core$load$fn__5066.invoke(core.clj:5641)
        at clojure.core$load.doInvoke(core.clj:5640)
        at clojure.lang.RestFn.invoke(RestFn.java:408)
        at clojure.core$load_one.invoke(core.clj:5446)
        at clojure.core$load_lib$fn__5015.invoke(core.clj:5486)
        at clojure.core$load_lib.doInvoke(core.clj:5485)
        at clojure.lang.RestFn.applyTo(RestFn.java:142)
        at clojure.core$apply.invoke(core.clj:626)
        at clojure.core$load_libs.doInvoke(core.clj:5524)
        at clojure.lang.RestFn.applyTo(RestFn.java:137)
        at clojure.core$apply.invoke(core.clj:626)
        at clojure.core$require.doInvoke(core.clj:5607)
        at clojure.lang.RestFn.invoke(RestFn.java:408)
        at umbel.listener$loading__4958__auto__.invoke(listener.clj:1)
        at clojure.lang.AFn.applyToHelper(AFn.java:152)
        at clojure.lang.AFn.applyTo(AFn.java:144)
        at clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3553)
        ... 29 more
Subprocess failed

Then I started looking where the issue may come from. I checked the content of the /target/classes/ directory. I found that the cls_index folder has been created and populated with the *.class files.

I see that the following class files got created:

core$find_L$fn__3635.class
core$find_l$fn__3640.class
core$find_L.class

However, I really don't know:

What is the issue
Why it is only an issue when generating a WAR file

Note: I also clearer the target folder using lein clean (just in case...) but this has no effect

A. Webb A. Webb · Accepted Answer · 2014-07-08T19:40:03

This problem occurs because

the library uses functions with the same name, but different case, such as find_l and find_L.
your file system is case insensitive

The hint is here:

java.lang.NoClassDefFoundError: clj_index/core$find_L 
  (wrong name: clj_index/core$find_l)

During compilation the class file for name with one case is overwritten with the classfile for the name with the second case.

This issue only occurs when you force AOT compilation, as when creating a uberwar with {:aot :all}.

Clojure: NoClassDefFoundError with lein ring uberwar but not when I Compile with the REPL

1 Answers