While working on App Engine's new Java runtime, we realized that we were missing something important. Something the Python runtime already had. Something sleek, yet powerful ... and approximately 80 characters wide and 25 characters tall. Yes, we're talking about the Python runtime's nifty shell demo app.
This helps us underscore two important compatibility features of Java App Engine:
Now, it must be said: please note that this is a demonstration app we developed to show off the power and flexibility of our new Java runtime; it's not a production service, and you shouldn't rely on it for anything important. Further, since this is a single shared instance of this application, running server code code from many users at once, you should exercise caution in entering any sensitive data like passwords into this demo. Finally, though we've worked to ensure rich functionality for as many languages as possible, this is still a proof of concept, and there is surely some language functionality missing from our environment.
But, without further ado, may we present to you, the Lord of the REPLS.
-- Google Software Engineers, Toby Reyelts and James Robinson.