这是NetBeans中的一个已知错误： http://www.netbeans.org/issues/ show_bug.cgi？id = 144243 您可以通过在NetBeans bug跟踪器中为此问题添加注释来帮助devolpers修复此问题。

I am just getting started with Grails. How do I add Java libraries to my Grails project? I added the Smack library jar to the lib folder of my Grails project, but I still cannot import any of its packages into my Java or Groovy classes. I am using the Netbeans IDE. Any help would be appreciated..

Buzzy

This is a know bug in NetBeans: http://www.netbeans.org/issues/show_bug.cgi?id=144243

Maybe you can help the devolpers to fix it by adding a comment to this issue in the NetBeans bug tracker.