What is the correct usage of "A is to B as C is to D"?

This confused me for a long time. Are the following sentences correct? (The words "Java" and "JavaScript" below are two computer languages whose names are kind of similar but indeed very different.)

1. Java is to JavaScript as ham is to hamster.
2. What Java to JavaScript is like (what) ham to hamster.
3. What Java is to JavaScript is like (what) ham is to hamster.

The first one is a common joke in computer science area, but it doesn’t look like a complete sentence. I always use the second or the third one, and people understood them perfectly, but I doubt if I can use them this way. What is the correct way for it and how can I use it in a sentence?

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Update:
I wanna clarify some confusion of my question. I would like to know, if someone ask me a question like "What is the difference between Java and JavaScript?" What should I answer as a complete sentence. Is it possible I can directly answer:"Java is to JavaScript as ham is to hamster"?