Umple provided several different means of examples.
Please http://try.umple.org. Umple is available online (no installation required), where you will be able to load several examples. Simply click on "Load & Save" to view and play with the examples, including both UML class diagrams and Umple source code. You can edit the diagram and see the code change, or vice-versa. The following are direct links to examples in UmpleOnline:
If you are interested in seeing Umple used to its fullest extent, then take a look at its test cases:
See the UmpleOnline source code