I keep getting this error "java.lang.NoClassDefFoundError: com/nomagic/magicdraw/uaf/UAF"

on line: uaf = com.nomagic.magicdraw.uaf.UAF.getInstanceByProject(project);

Here is my code:

import com.nomagic.magicdraw.core.Project;
import com.nomagic.magicdraw.uaf.UAF;
import com.nomagic.profiles.ProfileImplementation;

project = Application.getInstance().getProject();
UAF uaf = com.nomagic.magicdraw.uaf.UAF.getInstanceByProject(project);
List lstConsumingElement = new ArrayList();
lstConsumingElement.add(eleConsumingFcn);
for (Element consumingElement : lstConsumingElement){
	Abstraction abstraction = project.getElementsFactory().createAbstractionInstance();
	abstraction.setOwner(eleSource.getOwner());
	Elements.setClientElement(abstraction, eleSource);
	Elements.setSupplierElement(eleSource, consumingElement);
	uaf.isCapableToPerform().apply(abstraction);
}
List lstConformsTo = new ArrayList();
lstConformsTo.add(eleConformsTo);
uaf.isCapableToPerform().addConformsTo(newEle, eleConformsTo);
//Setting ConformsTo
uaf.uafElement().setConformsTo(newEle, lstConformsTo);