Scalatra could not find or load main class

Question

I have hello world scalatra application. I added scalatra-sbt plugin and:

val myDistSettings = DistPlugin.distSettings ++ Seq(
    mainClass in Dist := Some("WebServerLauncher"),
    memSetting in Dist := "2g",
    permGenSetting in Dist := "256m",
    envExports in Dist := Seq("LC_CTYPE=en_US.UTF-8", "LC_ALL=en_US.utf-8"),
    javaOptions in Dist ++= Seq("-Xss4m",
      "-Dfile.encoding=UTF-8",
      "-Dlogback.configurationFile=logback.prod.xml",
      "-Dorg.scalatra.environment=production")
  )

After making sbt dist it generates .zip with:

#!/bin/env bash

export CLASSPATH="lib:lib/logback-core-1.0.6.jar:lib/jetty-webapp-8.1.8.v20121106.jar:lib/jetty-io-8.1.8.v20121106.jar:lib/scalatra-scalate_2.10-2.2.2.jar:lib/jetty-server-8.1.8.v20121106.jar:lib/mime-util-2.1.3.jar:lib/scalatra-common_2.10-2.2.2.jar:lib/scalate-core_2.10-1.6.1.jar:lib/jetty-util-8.1.8.v20121106.jar:lib/jetty-servlet-8.1.8.v20121106.jar:lib/joda-convert-1.2.jar:lib/juniversalchardet-1.0.3.jar:lib/slf4j-api-1.7.5.jar:lib/scala-library-2.10.4.jar:lib/jetty-continuation-8.1.8.v20121106.jar:lib/grizzled-slf4j_2.10-1.0.1.jar:lib/config-1.0.0.jar:lib/javax.servlet-3.0.0.v201112011016.jar:lib/jetty-xml-8.1.8.v20121106.jar:lib/rl_2.10-0.4.4.jar:lib/jetty-security-8.1.8.v20121106.jar:lib/akka-actor_2.10-2.1.2.jar:lib/jetty-http-8.1.8.v20121106.jar:lib/scala-reflect-2.10.0.jar:lib/scalate-util_2.10-1.6.1.jar:lib/logback-classic-1.0.6.jar:lib/scalatra_2.10-2.2.2.jar:lib/joda-time-2.2.jar:lib/scala-compiler-2.10.0.jar:"
export JAVA_OPTS="-Xms2g -Xmx2g -XX:PermSize=256m -XX:MaxPermSize=256m -Xss4m -Dfile.encoding=UTF-8 -Dlogback.configurationFile=logback.prod.xml -Dorg.scalatra.environment=production"
export LC_CTYPE=en_US.UTF-8
export LC_ALL=en_US.utf-8

java $JAVA_OPTS -cp $CLASSPATH WebServerLauncher

When i'm trying to run it i got:

Error: Could not find or load main class WebServerLauncher

There is WebServerLauncher.class in lib directory.

How to correctly launch it?

Thank you.

Answer 1

I was having the exact same problem today.

What I found is that the generated script is path-dependent. That is, you do NOT execute it from within the bin directory, but one directory higher, in dist.

You then execute bin/YOURSCRIPTNAME and it should work.

I figured this out when I noticed that the path for the CLASSLIB weas lib/WHATEVER (relative path). The only place this path would be correct would be from the dist directory.

Hope this helps.