Most probably because, in your build.sbt, you didn't enable the -Xexperimental compiler flag for Scala. This is required when using Scala 2.11 (as you do) to enable SAM for Java 8 lambda support. Because this compiler flag is not set your build fails because it can translate `_.toUpperCase()` into a Java 8 lambda.
See https://github.com/confluentinc/examples/blob/kafka-0.10.0.0-cp-3.0.0/kafka-streams/pom.xml#L209-L214 . Also, note that your build.sbt is not equivalent to your pom.xml. For example, the org.apache.kafka:kafka-clients dependency is missing in build.sbt. On Sat, Aug 27, 2016 at 2:01 PM, Tommy Go <deeplam...@gmail.com> wrote: > Hi > > I am playing with kafka-streams using Scala, but found some strange issue, > the following project compiles using mvn but failed using sbt: > > https://github.com/deeplambda/kstream-debug > > [error] /Users/tommy/tmp/kstream-debug/src/main/scala/kafka/ > streams/WordCountDemo.scala:49: > missing parameter type for expanded function ((x$1) => > x$1.toUpperCase()) > [error] val uppercasedWithMapValues: KStream[Array[Byte], String] > = textLines.mapValues(_.toUpperCase()) > [error] > ^ > [error] one error found > [error] (compile:compileIncremental) Compilation failed > > > > Any ideas why the demo failed compiling using sbt ? > > Thanks, > Tommy >
