sbt-assembly: deduplication found error

Question

Add the code below to your build.sbt file

assemblyMergeStrategy in assembly := {
 case PathList("META-INF", xs @ _*) => MergeStrategy.discard
 case x => MergeStrategy.first
}

This helped me a lot.

Use the "provided" configuration, which will scope your dependent library.

For example:

libraryDependencies += "org.apache.spark" %% "spark-core" % "1.1.0" % "provided"

If needed, read more at

https://github.com/sbt/sbt-assembly#excluding-jars-and-files

import AssemblyKeys._

name := "approxstrmatch"

version := "1.0"

scalaVersion := "2.10.4"

// unmanagedJars in Compile += file("lib/secondstring-20140729.jar")

libraryDependencies+="org.apache.spark"%%"spark-core"%"1.0.0"

libraryDependencies ++= Seq(
    ("org.apache.spark"%%"spark-core"%"1.0.0").
    exclude("org.eclipse.jetty.orbit", "javax.servlet").
    exclude("org.eclipse.jetty.orbit", "javax.transaction").
    exclude("org.eclipse.jetty.orbit", "javax.mail").
     exclude("org.eclipse.jetty.orbit", "javax.activation").
    exclude("commons-beanutils", "commons-beanutils-core").
    exclude("commons-collections", "commons-collections").
    exclude("commons-collections", "commons-collections").
    exclude("com.esotericsoftware.minlog", "minlog")
)


resolvers += "AkkaRepository" at "http://repo.akka.io/releases/"



 lazy val app = Project("approxstrmatch", file("approxstrmatch"),
    settings = buildSettings ++ assemblySettings ++ Seq(
    mergeStrategy in assembly <<= (mergeStrategy in assembly) { (old) =>
    {
        case PathList("javax", "servlet", xs @ _*)         => MergeStrategy.first
        case PathList("javax", "transaction", xs @ _*)     => MergeStrategy.first
        case PathList("javax", "mail", xs @ _*)     => MergeStrategy.first
        case PathList("javax", "activation", xs @ _*)     => MergeStrategy.first
        case PathList(ps @ _*) if ps.last endsWith ".html" => MergeStrategy.first
        case "application.conf" => MergeStrategy.concat
        case "unwanted.txt"     => MergeStrategy.discard
        case x => old(x)
        }
    })
  )


mainClass in assembly := Some("approxstrmatch.JaccardScore")
// jarName in assembly := "approstrmatch.jar"

The module-info.clas file has moved in many libraries. Here is the updated solution

ThisBuild / assemblyMergeStrategy  := {
  case PathList("module-info.class") => MergeStrategy.discard
  case x if x.endsWith("/module-info.class") => MergeStrategy.discard
  case x =>
    val oldStrategy = (ThisBuild / assemblyMergeStrategy).value
    oldStrategy(x)
}