NPE with null key

[hakandilek]

NullPointerException occurs if key is null:

    at com.avaje.ebeaninternal.server.core.DefaultServer.find(DefaultServer.java:1072)
    at com.avaje.ebeaninternal.server.core.DefaultServer.find(DefaultServer.java:1063)
    at play.db.ebean.Model$Finder.byId(Model.java:261)
    at play.utils.cache.CachedFinder.byId(CachedFinder.java:63)
    at play.utils.dao.CachedDAO.get(CachedDAO.java:45)