scala
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.lang.String.format("%3d", 1) ^ scala> java.lang.String.format("%03d", 1.asInstanceOf[Object]) res2: java.lang.String = 001
これはうれしくないなぁ〜。