Exception when running `lein cljsbuild once` about assistant

[29decibel]

Did you use the latest leiningen? Please make sure using >=2.5.1

[vhpoet]

@29decibel I have 2.5.2 installed. Here's the full exception

11:28 $ lein cljsbuild once && lein node-webkit-build
Compiling ClojureScript.
Exception in thread "main" java.lang.UnsupportedClassVersionError: com/google/javascript/jscomp/CompilerOptions : Unsupported major.minor version 51.0, compiling:(cljs/closure.clj:1:1)
    at clojure.lang.Compiler.load(Compiler.java:7142)
    at clojure.lang.RT.loadResourceScript(RT.java:370)
    at clojure.lang.RT.loadResourceScript(RT.java:361)
    at clojure.lang.RT.load(RT.java:440)
    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$use.doInvoke(core.clj:5618)
    at clojure.lang.RestFn.invoke(RestFn.java:436)
    at cljsbuild.compiler$eval9$loading__4958__auto____10.invoke(compiler.clj:1)
    at cljsbuild.compiler$eval9.invoke(compiler.clj:1)
    at clojure.lang.Compiler.eval(Compiler.java:6703)
    at clojure.lang.Compiler.eval(Compiler.java:6692)
    at clojure.lang.Compiler.load(Compiler.java:7130)
    at clojure.lang.RT.loadResourceScript(RT.java:370)
    at clojure.lang.RT.loadResourceScript(RT.java:361)
    at clojure.lang.RT.load(RT.java:440)
    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$require.doInvoke(core.clj:5607)
    at clojure.lang.RestFn.invoke(RestFn.java:436)
    at user$eval5.invoke(form-init3522142005837967367.clj:1)
    at clojure.lang.Compiler.eval(Compiler.java:6703)
    at clojure.lang.Compiler.eval(Compiler.java:6692)
    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.UnsupportedClassVersionError: com/google/javascript/jscomp/CompilerOptions : Unsupported major.minor version 51.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
    at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:171)
    at cljs.closure$eval111$loading__4958__auto____112.invoke(closure.clj:9)
    at cljs.closure$eval111.invoke(closure.clj:9)
    at clojure.lang.Compiler.eval(Compiler.java:6703)
    at clojure.lang.Compiler.eval(Compiler.java:6692)
    at clojure.lang.Compiler.load(Compiler.java:7130)
    ... 54 more
Subprocess failed

[29decibel]

Hi @vhpoet Could you also verify what Java version you use? According to this it seems like the Google Closure compiler needs at least Java7, Java8 would be better.

cemerick commented on Dec 15, 2014
ClojureScript (or Google Closure, not sure exactly which) has required Java 7 for a little while now. I've updated dependencies in the sample project.clj files.

If upgrading Java could solve your problem, I will udpate the readme.