Objects that are unmarked at the end of the mark phase are unreachable by the application (dead) because there's no path from the root set through any series of references to find them.
Once the CPU utilization on the application server approaches and hits the 100% mark, any increase in the number of users only results in poorer response times.
一旦应用程序服务器上的CPU利用率接近并达到100%分，用户数量的增加只会导致更长的响应时间。
3
The same mark-sweep-compact collector is used, but much of the mark and sweep phases can be done as the application runs.