Comment by gf000

Do you need extra-low latency, even at very high percentile and are willing to give away a bit of throughput for it? ZGC

At almost every other case: G1 (the default, just don't add any flags).

Do you want to trade off using less memory at the price of some throughput? Decrease heap size, otherwise don't add anything.

That's it, in most cases just use the default.