Hello！today let's try to know ZGC.You know JDK8 默认垃圾收集器是Parallel Scavenge(新生代) + Parallel Old(老年代)，Parallel Scavenge收集器以并行的方式执行小规模的收集，这可以显著降低垃圾收集开销。而于 2018-09-25 正式发布的JDK11，里包括了ZGC: A Scalable Low-Latency Garbage Collector。由于ZGC出色的性能(实现垃圾收集的停顿不超过10ms)，使其在目前十多种垃圾收集器里，最璀璨夺目。OK， Let's go!

What is ZGC?

The Z Garbage Collector

The Z Garbage Collector (ZGC) is a scalable low latency garbage collector. ZGC performs all expensive work concurrently, without stopping the execution of application threads for more than 10ms, which makes is suitable for applications which require low latency and/or use a very large heap (multi-terabytes).

Z垃圾收集器（ZGC）是一个可伸缩的低延迟垃圾收集器。 ZGC可以同时执行所有昂贵的工作，而不会将应用程序线程的执行停止超过10毫秒，这使得它适用于需要低延迟和使用非常大的堆（目前ZGC可管理4TB以内的堆）的应用程序。

The Z Garbage Collector is available as an experimental feature, and is enabled with the command-line options -XX:+UnlockExperimentalVMOptions -XX:+UseZGC.

Z Garbage Collector可作为实验功能使用，并通过命令行选项-XX：+
UnlockExperimentalVMOptions -XX：+ UseZGC启用。

英文选自
https://docs.oracle.com/en/java/javase/11/gctuning/z-garbage-collector1.html#
GUID-A5A42691-095E-47BA-B6DC-FB4E5FAA43D0