[Java] JVM configuration

jvm 3 areas

1,young generation New new object 2,old generation Objects that have been used for a long time 3,permanent generation Information such as Class, method, etc.

Setting JVM memory parameters

Maximum heap size -Xmx5M: Maximum heap size 5M
Minimum heap size -Xms3M 3, new generation size -Xmn 4, permanent size -XX:PermSize -XX:MaxPermSize

How GC works 1,ScanVengeGC Target: young generation only Speed: fast Frequency: Frequent How it works: Copy only the object in use to survivor1 (to) without Survivor0 (From) Empty Survivor0 (From). 2,FullGC Target: young generation and old generation Speed: slow Frequency: Not generally done Execution timing: Memory is not released when running ScaVenge GC If not executed, out of memory error will occur How it works: Mark obj in use ---> Delete unused parts ---> Move fragmented memory to continuous memory

test https://github.com/YanHengGo/java