[DannyBee]

Yes, but in hotspot's case I cannot remember if it is actually turned on in both "server" and "client"

[pjmlp]

Aren't server and client not now merged with tiered compilation in Hotspot?

[DannyBee]

No, AFAIK. "Tiered compilation, introduced in Java SE 7, brings client startup speeds to the server VM. ... Tiered compilation is now the default mode for the server VM. "

Again, AFAIK, the server VM still has a significantly different set of tuning than the client VM. In particular, it runs some significantly more complex opts that the client VM does not.