A logger enables to output information directly into the active Enterprise Architect application Output view:
import com.sodius.mdw.metamodel.uml21.io.ea.com.EAApplicationLogger;
...
EAApplicationLogger logger = new EAApplicationLogger("MyTab");
logger.clear(); // clear existing entries in the tab
logger.info("Logging a message")
logger.error("Logging an issue");

Writing UML Data
Writing Enterprise Architect Data

MDAccess for UML API Reference
MDAccess for MagicDraw API Reference