Not true if you mean that their syntaxes are compatible, they are quite different.
Maybe I was thinking of Groovy.
Sorry, commenting before morning coffee :)
Scala introduces new versions of collections like Map and List that aren't compatible with Java's versions. The syntactic sugar only works with the Scala Maps.
Meanwhile, Groovy uses Java collections.
Luckily, in Scala there's a JavaConversions package that allows you to cast back and forth from Maps, Lists, Sets, etc, to whatever Scala type you want.