Wrong warning "Could not initialize class my.pkg.ArchiveBuilder" by Arquillian

I'm using JBoss Tools 41-Update-2013-05-19_01-13-51-B207 having the new Arquillian component.

I'm getting a warning "Could not initialize class my.pkg.ArchiveBuilder" in all Arquillian-based test classes.

In fact my ArchiveBuilder isn't a regular class, but it's an enum:
public enum ArchiveBuilder {
INSTANCE;
private final WebArchive archive = ShrinkWrap.create(WebArchive.class, "shop.war");
private ArchiveBuilder()

public static ArchiveBuilder getInstance()

public Archive<? extends Archive<?>> getArchive()