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YongGC, MinorGC, MajorGC, Old GC, Full GC who is who? Dizzy! This article explains in particular

Here we bring some nouns for you to add the explanation, such as MinorGC, YongGC, Full GC, OldGC, Major GC, Mixed GC, maybe everyone is a little confused and vague when saying, why there are so many words? Which represents the new generation, the old age?

In fact, there is no unified standard and definition for this term in the industry, and it is also different in some books. If it is not clear in the interview, it may be different from the interviewer’s understanding, so let’s explain it together:

(1) Minor GC/YongGC

The new generation, the younger generation, the younger generation The new generation GC can be either YongGC or MinorGC.

(2) Old GC, Old GC?

Before we said that the Old GC always used Full GC, did not mention the Old GC, of course, if to say the Old GC alone, then it is more appropriate to use Old GC. The Old GC is also used when we refer to the Old GC. (Of course, if you use Full GC, there is no problem. In general, Old GC will be triggered either before or after a Minor GC, so we just call it Full GC.)

(3) Full GC

First of all, Full GC refers to garbage collection of all memory space for new generation, old generation, permanent generation, so it is called Full GC.

(4) Major GC

Said a lot of books or blog some Major GC = = Old GC, also have said = = Full GC, the word is very confused, so personal advice not to mention the word as far as possible, if there is an interview the interviewer said to the word, you can clarify to him is refers to the older generation of recycling or a whole heap of recycling.

(5) Mixed GC

Mixed GC is a special concept in G1. When the memory of the old generation reaches 45%, the Mixed GC is triggered to collect both the new generation and the old generation.