> In Scala, it's this. Some would argue you don't even need a separate method.
It seems a bit unfair to force null checks on the Java code and then present a Scala alternative that throws NPE in two different places.
Option(s).getOrElse(List[String]()).filter(str => Option(str).fold(false)(_.length > 5)) def foo(s: List[String]): List[String] = s match { case l: List[String] => l.filter(_ match { case str: String => str.length > 5; case _ => false}); case _ => List[String]()}
You're right that this is primarily a concern if the Scala dev wants to talk to Java. However, if the Scala dev does not want to talk to Java, perhaps a statically typed FP language with an HM type system would be a better fit.