EL in ZK 6 I had some issues trying to figure out some basic stuff since I didn't see it documented anywhere.

For concatenation I seemed to have to use el2's concat function...

For equals you can't use == , need to use el's 'eq' or 'ne'

visible="@load(productGroup.owner.id eq user.id)" 

Groovy - using a writer with FileIO

Groovy - using a writer with FileIO

public void writeToFile(def directory, def fileName, def extension, def infoList) {
  new File("$directory/$fileName$extension").withWriter { out ->
    infoList.each {
      out.println it
    }
  }
}