The class located in knowledge-api/src/main/java/org/drools/time/Calendar.java defines package org.drools.core.time instead of org.drools.time.
Not sure this issue is actually there in Beta3: https://github.com/droolsjbpm/drools/blob/6.0.0.Beta3/knoweldge-api-legacy5-adapter/src/main/java/org/drools/time/Calendar.java I guess there might be some confusion with a knowledge-api module that is still there in the droolsjbpm-knowledge repository but that is not part of the built (so the code in there is never built, it's the module inside the drools repository that is producing the knowledge-api jar).
That's why I included also the link to the class on the call. https://github.com/droolsjbpm/droolsjbpm-knowledge/blob/6.0.0.Beta3/knowledge-api/src/main/java/org/drools/time/Calendar.java If it's not built then we don't have a problem.
It is not, as you can see here, only the kie-* modules are built: https://github.com/droolsjbpm/droolsjbpm-knowledge/blob/6.0.0.Beta3/pom.xml#L49 I'll check with the rest of the team about safely removing the code. Feel free to close the issue (NOTABUG?). Kris