The Volta suite is still in a prototype stage and has many known issues and limitations. It currently lacks support for:
Recursion
Polymorphism
Exception handling
switch, break, and continue statements
Inner and anonymous classes
In addition, a number of bugs exist in the supported features. For example, tree-based WCET calculation produces invalid results in the presence of return statements that are not the last statement in the method. A list of known bugs can be found in the Volta Bugs Tracker.