f96c6a36_EMF_v1_0_Users__Guide__Java
[Property] basePackage [UML] basePackage property is specified on the eCore page of the specification dialog for the UML Package. [XMI] basePackage attribute on the subPackages element in the genmodel document. [Java] 
The base part of the Java package. This is the Java package that is specified on the package statement of the interfaces and/or classes contained in the package.
EMF v1.0 Users' Guide