To work with the uml files:
1 Install JDeveloper 10.1.3.2.0
2 Create a new application workspace (e.g. buildtoolViewer.jws)
3 Create a new project (e.g. uml.jpr)
4 Set the Model Path property for the project to the uml subdirectory in this package
  (e.g. ...\MASS_Dev_Infra\core_buildtool\src\uml)
  Right click on the project in the Applications Navigator.
  Select Project Properties.
  Open Project Content.
  Select Modelers.
  Add the full path to the uml subdirectory.
  Remove the default path.