Accessing static variable via OGNL returns nothing

Accessing static variables of a public class does not seem to work. I tried setting the struts.ognl.allowStaticMethodAccess = true in the project root's struts.properties but it didn't change anything.

<s:property value="@de.mytest.common.Constants@CONSTANT" default="Nothing" />

For this, I get "Nothing" as the output. It seems to have worked in 2.5.18.