When method setTimeSlice() of class Variable is invoked over a variable whose name doesn't contain  it converts the base name to null.
For example, try the next code:
Variable variableQoL = new Variable("QoL"); variableQoL.setTimeSlice(0);
The name of variableQoL is then "null ".
I don't want to modify the method because I don't know if the error is in the Javadoc or instead in the Java code.