Scala logging line numbers don't match using slf4s/slf4j?

Does anyone know if there is a way to do logging that outputs real line numbers to the console? I'm trying to get into Scala here, but without being able to get basic stuff like this that I depend on, it's really hard to get much going.

I have set up SLF4J to wrap with slf4j - log4j - jcl-over-slf4j. The problem is I get line numbers that do not match at all. The are much higher line numbers than the Scala class even contains. Is this because the line numbers are actually Java-intermediate line numbers?

Is there any EASY way to get set up logging that meets these requirements?:

1. interoperable, working with both Java & Scala
2. as easy to change the logging level of individual packages as easily as Log4j
3. provides ACCURATE line numbers.

I have found that logback (by Ceki Gülcü) works great and preserves line numbers too!
(And it works as a replacement for log4j: Awesome!)

import ch.qos.logback._
import org.slf4j._

object Main {

    def logger = LoggerFactory.getLogger("Main")
    var thingy = {
        x:Int =>
        logger.info("x=" + x)
        x + 1
    }
    def main(args: Array[String]) {
        logger.info("Hello.")
        logger.info("Hello again!")

        val myInts : List[Int] = List(-25,1,5,20)

        val myInts2 : List[Int] = myInts.filter { x:Int => x > 0 }

        logger.info("my ints2:" + myInts2)

        val myInts3 = myInts2.map(p =>  p * 2 )
        logger.info("my ints3:" + myInts3)

        logger.info(thingy(1) + "")
    }
}

For anyone struggling to get started with Scala, this is what I did to get the basic skeleton up:

1) Download sbt-launcher.jar and put it someplace like /opt/
I used "sbt-launch-0.7.5.RC0.jar"

2) Create a bash script as a shortcut to the sbt launcher in nano /opt/bin/sbt:

#!/bin/bash
java -jar /opt/sbt-launch-0.7.5.RC0.jar "$@"

(make it executable)

$ sudo chmod ug+x ./sbt

Make sure it's in your path too.

3) Create and configure the sbt project:

$ mkdir ./sc01
$ cd ./sc01
$ sbt
$ mkdir ./project/build</pre>
$ nano ./project/build/Project.scala</pre>

put this in there:

import sbt._

class sc01(info: ProjectInfo) extends DefaultProject(info)
{
    // dependencies
    val logback_core = "ch.qos.logback" % "logback-core" % "0.9.24" % "compile" //LGPL 2.1
    val logback_classic = "ch.qos.logback" % "logback-classic" % "0.9.24" % "compile" //LGPL 2.1
    val log4j_over_slf4j = "org.slf4j" % "log4j-over-slf4j" % "1.6.1"


   // if you are going to have any unmanaged (manually-added) jars
   //    def baseDirectories = "lib"
   //    def extraJars = descendents(baseDirectories, "*.jar")
   //    override def unmanagedClasspath = super.unmanagedClasspath +++ extraJars

    // tasks - easy to define
    lazy val hi = task { println("Hello World"); None }

    // classpath
    //override def mainScalaSourcePath = "src"

}

4) Paste the stuff from above into Main:

$ nano ./src/main/scala/Main.scala

5) I almost forgot! put this in /src/main/resources/logback.xml
(it's required to get the line numbers)

<configuration>

    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <!-- encoders are assigned the type
     ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} %line --- %msg%n</pattern>
        </encoder>
    </appender>

    <root level="debug">
        <appender-ref ref="STDOUT" />
    </root>
</configuration>

6) $ sbt

Now you should be in the sbt console in your shell:

> update
> compile
> run

Hope this helps.