scala - 如何修复 NoSuchMethodError？

Question

我使用 Scala 2.10.0RC1 和 sbt 0.12.1。什么原因以及如何修复此运行时错误（在 2.9.2 上运行良好）？

确切的错误信息是：

java.lang.NoSuchMethodError: scala.Predef$ArrowAssoc$.extension$$minus$greater(Ljava/lang/Object;Ljava/lang/Object;)Lscala/Tuple2;

Answer 1

You're running the code with the wrong Scala version. This can have several causes:

• misconfiguration of the project with sbt – search for 2.9.2 in config files
• stale cache used by sbt – sbt reboot
• something else?

If you meticulously check all your sbt configuration files for 2.9.2 and then wipe out all caches, things should run better. Dependencies usually have a version number in the name of the jar file, so running a find on your system will likely point you to the ones you missed.