[SOLVED] App running under SBT doesn't find a class from Classpath jar

App running under SBT doesn't find a class from Classpath jar

I have a Scala project using sbt. It runs perfectly well under Eclipse, however, trying to run it under sbt (sbt 'run mount 1440' — including the parameters I need) leads to a ClassNotFoundException — it can not find jnr.ffi.provider.jffi.NativeClosureProxy class. However, running sbt 'last run' shows me that jnr-ffi-2.0.3.jar file (which includes the said class) is actually included in the classpath. Any suggestions on what's happening?

Sources available on github: https://github.com/FileJunkie/vkfs

Solution

Your build sbt is invalid.

First, you need to have empty lines between the libraryDependecys.

lazy val root = (project in file(".")).
  settings(
    name := "vkfs",
    version := "1.0",
    scalaVersion := "2.11.7"
  )

libraryDependencies += "org.scalaj" %% "scalaj-http" % "1.1.6"

libraryDependencies += "org.json4s" %% "json4s-jackson" % "3.2.11"

libraryDependencies += "com.github.serceman" % "jnr-fuse" % "0.1"

Second, the dependency "com.github.serceman" can not be resolved. This means either that

you installed the dependency manually to your Ivy-repository at .ivy or
you have not specified a correct resolver ( see http://www.scala-sbt.org/0.13/docs/Resolvers.html )

So in summary, it seems that Eclipse does something automatically, so your program runs. When it comes to your build.sbt it is not valid (empty lines missing) and does not resolve dependencies properly. I wonder, how you could start via sbt 'run mount 1440' at all.

After correcting the empty lines and running sbt 'run mount 1440' I obtain

Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=256M; support was removed in 8.0
[info] Set current project to vkfs (in build file:/home/.../IdeaProjects/vkfs/)
[info] Updating {file:/home/.../IdeaProjects/vkfs/}root...
[info] Resolving com.github.serceman#jnr-fuse;0.1 ...
[warn]  module not found: com.github.serceman#jnr-fuse;0.1
[warn] ==== local: tried
[warn]   /home/.../.ivy2/local/com.github.serceman/jnr-fuse/0.1/ivys/ivy.xml
[warn] ==== public: tried
[warn]   http://repo1.maven.org/maven2/com/github/serceman/jnr-fuse/0.1/jnr-fuse-0.1.pom
[info] Resolving jline#jline;2.12.1 ...
[warn]  ::::::::::::::::::::::::::::::::::::::::::::::
[warn]  ::          UNRESOLVED DEPENDENCIES         ::
[warn]  ::::::::::::::::::::::::::::::::::::::::::::::
[warn]  :: com.github.serceman#jnr-fuse;0.1: not found
[warn]  ::::::::::::::::::::::::::::::::::::::::::::::
sbt.ResolveException: unresolved dependency: com.github.serceman#jnr-fuse;0.1: not found
at sbt.IvyActions$.sbt$IvyActions$$resolve(IvyActions.scala:213)
at sbt.IvyActions$$anonfun$update$1.apply(IvyActions.scala:122)
at sbt.IvyActions$$anonfun$update$1.apply(IvyActions.scala:121)
[ ... truncated ... ]

Edit (concerning dependency from jcenter)

Add the following line to your build.sbt (remember extra empty line)

resolvers += Resolver.jcenterRepo

to add jcenter to your resolver list.

Edit 2

Resolver.jcenterRepo is not available in SBT 0.13.5, thus

resolvers += "jcenter" at "https://jcenter.bintray.com/"

is required.

After successful compilation and run the relevant error is

java.lang.RuntimeException: java.lang.NoClassDefFoundError: jnr/ffi/provider/jffi/NativeClosureProxy
at jnr.ffi.provider.jffi.NativeClosureProxy.newProxyFactory(NativeClosureProxy.java:220)

Final result

The library "com.github.serceman" in v 0.1 seems to be problematic, as it can not properly instantiate some class via reflection.

Solution

Problem solved by adding fork in run := true to build.sbt.