What exactly does the letter "Z" refer to in the name ZGC in JDK11?

Question

I have heard that JDK 11 introduces a new garbage collector strategy named ZGC, but I cannot find what this stands for. What does the letter "Z" mean? Does it have any specific meaning?

Answer 1

It's just a name with no deeper meaning.

When naming ZGC they were inspired by / wanted to pay homage to Oracle's Bonwick's filesystem ZFS.

Bonwick explains the meaning of "Z" in ZFS in his Blog. He tried to come up with a good name and finally decided on something with "FS". Looking through AFS-ZFS it turned out that all were being used, but ZFS not so much. From (2):

So in the end, I picked ZFS for the simplest of reasons: it sounds cool. It doesn't come with any baggage, like YFS (Why FS? Ha ha!). And you can even say it in hex (2f5).

Next he wanted to come up with something "Z" could stand for and possible candidates were "Zero" or "Zetta" (but the he'd have to explain what Zetta means) and then (2):

So we finally decided to unpimp the name back to ZFS, which doesn't stand for anything. It's just a pseudo-acronym that vaguely suggests a way to store files that gets you a lot of points in Scrabble.

And since the "Z" in ZFS doesn't stand for anything, so does now the "Z" in ZGC.

Sources:

1. Entry in the ZGC FAQ: What does the "Z" in ZGC stand for?
2. Jeff Bonwick's Blog (2006): You say zeta, I say zetta

Additional information: The FAQ also informs us that you are free to pronounce it "zed gee see" or "zee gee see".