In the another post, I give a short introduction of GC.
Now for the practical purpose, I need to focus on the common used GCs: Parallel GC, CMS and G1.
What is the tracing algorithm and mark-and-sweep method?
Root objects are the starting point of marking phase. Usually, root object references are located in the thread stacks.
Every object has its fields, if a field is a object reference, then the reference will be like a pointer to another object.
From the point of whole heap, these objects will form an object graph.
GC process illustrations
tuning the minor GC
tuning the full GC