I am preparing to teach students python, in addition to java. 

Usually, I test a proof of concept (POC) of my teaching with a handful of students, so as to know if my lesson plans are good (I teach the lesson to 4-6 students of varying skill and then I ask them for feedback). This time, the students were introduced to Python, after they were taught Java (They were taught OOP and basic I\O).

For the POC lesson in python, the feedback I received showed the difficulty in understanding the difference between Python and Java. Python felt so different (and rightly so) to the students, and they couldn't quite understand how it works, when compared to java. They know java has the runtime environment which runs compiled code, but they don't know how python runs the code they write. This difference I'm referring to. That isn't the only difference they had difficulty with.

So, in an attempt to make the introductory lesson in python to the rest of the students, I am trying to explain those differences beforehand. 

How can make the transition\introduction from java to python more smooth?