Grails Runtime Exception

Error Details

Error 500: Executing action [show] of controller [com.siebnich.MyFileController] caused exception: Provided id of the wrong type for class com.siebnich.MyFile. Expected: class java.lang.Long, got class java.lang.String; nested exception is org.hibernate.TypeMismatchException: Provided id of the wrong type for class com.siebnich.MyFile. Expected: class java.lang.Long, got class java.lang.String
Servlet: grails
URI: /grails/myFile/show.dispatch
Exception Message: Provided id of the wrong type for class com.siebnich.MyFile. Expected: class java.lang.Long, got class java.lang.String
Caused by: Provided id of the wrong type for class com.siebnich.MyFile. Expected: class java.lang.Long, got class java.lang.String
Class: MyFileController
At Line: [18]
Code Snippet:

Stack Trace

org.hibernate.TypeMismatchException: Provided id of the wrong type for class com.siebnich.MyFile. Expected: class java.lang.Long, got class java.lang.String

at com.siebnich.MyFileController$_closure2.doCall(MyFileController.groovy:18)
at com.siebnich.MyFileController$_closure2.doCall(MyFileController.groovy)
at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:283)
at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:767)
at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:697)
at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:889)
at java.lang.Thread.run(Thread.java:722)