gistfile1.scala

object MyJGitSample {

  import scalaz._
  import scalaz.effect.IO

  def lift[T](f: => T) = EitherT(IO(\/.fromTryCatchNonFatal(f)))
  def abortIf(b: Boolean, msg: String) = EitherT(IO(if (b) -\/(new Throwable(msg)) else \/-(())))

  def createCommand = {

    import org.eclipse.jgit.api._
    import org.eclipse.jgit.internal.storage.file.FileRepository

    val localPath = ".";
    val localRepo = new FileRepository(localPath + "/.git")
    val git = new Git(localRepo)


    for {
      addAll <- lift(git.add().addFilepattern("*").call.getEntryCount)
      st <- lift(git.status.call())
      _ = println(st.getUncommittedChanges)
      _  <- abortIf(st.getUncommittedChanges.isEmpty, "No committed change")
    } yield addAll
    
  }
  
  def main(args: Array[String]) = {
    println(createCommand.run.unsafePerformIO)
    
  }
}

Here are the sbt dependencies used in this sample : 

• "org.eclipse.jgit" % "org.eclipse.jgit" % "3.7.0.201502260915-r"
• "org.scalaz" %% "scalaz-core" % "7.1.1"
• "org.scalaz" %% "scalaz-effect" % "7.1.1"

looks good, but pretty tough to read due to scalaz.
Thanks a lot for pointing me to this implementation.