Heap中新生代和老年代的区别

Question

I have read that new generation stores newly created objects while tenured generation stores object which survives. But I have a doubt that how will compiler know that particular object will survive or not? When will it put particular object in tenured generation? Please guide me.

Answer 1

The young generation is divided into 3 spaces.

• One Eden space
• Two Survivor spaces

There are 3 spaces in total, two of which are Survivor spaces. The order of execution process of each space is as below:

1. The majority of newly created objects are located in the Eden space.
2. After one GC in the Eden space, the surviving objects are moved to one of the Survivor spaces.
3. After a GC in the Eden space, the objects are piled up into the Survivor space, where other surviving objects already exist.
4. Once a Survivor space is full, surviving objects are moved to the other Survivor space. Then, the Survivor space that is full will be changed to a state where there is no data at all.
5. The objects that survived these steps that have been repeated a number of times are moved to the old generation.

The information is taken from this article . I'd suggest to read it for deeper understanding.