Java JVM Memory Cheat Sheet
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The document outlines the structure of Java memory management, specifically the heap segment which includes young, old, and survivor objects, as well as the stack segment containing local and reference variables. It also mentions components like metaspace and code cache related to off-heap memory. The author identifies themselves as a senior Java consultant with over ten years of experience.
Java JVM Memory Cheat Sheet
- 1. 1 H E A P S E G M E N T L I V E E X A M P L E Contains all created objects in runtime, objects only plus their object attributes (instance variables) = Young (new objects that die more often than old ones) - Eden - Survivor 1 - Survivor 2 = Old (objects that outlived several Garbage Collectors cycles) 2 S T A C K S E G M E N T ( O F F - H E A P ) Contains local variables and Reference variables (variables that hold the address of an object in the heap = Stack (-Xss, max memory, it is around 2000 threads for average enterprise app. , 2000 x 1mb = 2GB ) = Metaspace (-XX:MetaspaceSize=256m) = Code Cache(-XX:InitialCodeCacheSize 100 mb) 3 C O D E S E G M E N T ( O F F - H E A P ) The segment where the actual compiled Java bytecodes resides when loaded JAVA MEMORY MODEL CHEAT SHEET T Y P E S I Z E S MynameisMarkand I'mJavaSenior Consultantwith+10 yearsofexperience