scala> format("%03d",1) res2: String = 001Predefにあるぢゃないか。 アホだ、おれ。

scala> java.lang.String.format("%03d", 1) <console>:6: error: type mismatch; found : Int required: java.lang.Object Note: primitive types are not implicitly converted to AnyRef. You can safely force boxing by casting x.asInstanceOf[AnyRef]. java.la</console>…