What is the difference between G1 GC’s young, survivor, and old regions and what triggers a mixed collection?

Question

Java Professional — Hard

What is the difference between G1 GC’s young, survivor, and old regions and what triggers a mixed collection?

Accepted Answer

G1 GC divides the heap into regions for Eden, Survivor, and Old. A mixed collection is triggered when the old region occupancy exceeds a certain threshold. This collects both young and selected old regions.