Evals from Java

Hi all, 
I know nothing whatsoever about Python. I just downloaded Jython oin the recommendation of someone in some forum responding to a question about how to evaluate strings from Java - it turns out that the standaard libraries provide no real way to do this. 

I have a very simple situation - I have a string with a basic mathmatical _expression_, like  "3+45*2" and I want to store it's value in an int from a Java program. 

From the documentation i read, it seems Jython is mainly concerned with using Java from within Python, but it seems that it is also possible to run Python from within Java - however, most of the documentation was over my head, and about more complex things. Is there a relatively simple way to do this? 

Thanks!

Jake