Inferred Types

A variable declaration in a for-each loop can make use of var to infer its type.

class Main {
   void main() {
String[] chairMaterials = { "wicker", "wood", "plastic" }
for (var chairMaterial : chairMaterials) {
    IO.println(chairMaterial);
}
   }
}

And this is good to know for the same reasons you would use var other places in Java. Writing Book book can be a drain on the soul.