This article is a personal learning "from 0 to take you to become a master JVM real" content summary details of the two-dimensional code scanning
1, the foregoing review
5 weeks before analysis of the JVM core principles, problem situations GC occurs.
2. What are most afraid of running on the JVM system?
Caton problems caused by STW
.png)
3, in the end the young generation gc How often has little effect on the system?
How often needs to be based on business.
Gc influence on the young generation systems are not so big? Relative to FullGC, is little impact on the system
4, when the new generation gc great impact on the system?
System deployment deployed on large memory machines, your application is assigned to
dozens of G
, while
under high load situations
(such as tens of thousands of requests per second), then a backlog of more than a lot of survival, resulting in a long recovery time
5, the new generation how to solve large memory machines GC too slow problem?
G1 garbage collector, G1 naturally suited to this JVM to run large memory machines can be the perfect solution to the problem of long large memory garbage collection time.
6, terrible years old frequent problem gc
Three conditions to enter old age: 1, 2 older dynamically determine the age of 3, Survivor does not fit focus on 2 and 3. Therefore, in accordance with said before, estimating memory model, a rational allocation of memory
7, JVM optimized performance optimization in the end what?
The general principle: the rational allocation of memory allocation, as far as possible not on FullGC