Zoom on java Garbage collector

Zoom on Java Garbage policy and collectors (in fact just an introduction zoom, lot more to explore around)

Introduction Garbage collector and Garbage policy

• intro http://www.baeldung.com/jvm-garbage-collectors
• intro to main concern, the why of GC policy https://shipilev.net/jvm-anatomy-park/3-gc-design-and-pauses/

A book : “The Garbage Collection Handbook: The Art of Automatic Memory Management (Chapman & Hall/CRC Applied Algorithms and Data Structures series)” To go deeper in the mechanism

Tuning : choose your policy and tune it

“gc tuning confessions of a performance engineer” de Monica Beckwith

• VJug video https://www.youtube.com/watch?v=P2srlsVrrKA
• Slides https://fr.slideshare.net/MonicaBeckwith/gc-confessions

Java 8 GC Tuning https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/

Java 9 GC Tuning https://docs.oracle.com/javase/9/gctuning/toc.htm

JVM GC Options http://blog.ragozin.info/2016/10/hotspot-jvm-garbage-collection-options.html JVM option Cheat Sheet https://zeroturnaround.com/rebellabs/jvm-options-cheat-sheet/

Do not forget to get your logs to check impact (take care, big changes with Java 9)

• https://fr.slideshare.net/PoonamBajaj5/lets-learn-to-talk-to-gc-logs-in-java-9
• https://blog.gceasy.io/2017/10/17/disruptive-changes-to-gc-logging-in-java-9-what-you-need-to-do/

New comers in town

• Java oracle (Hotspot) G1. Introduced with JDK7 update 4, default Garbage collector on Java 9
• C4 AzulSystem garbage collector (Zing JVM)
• Shenandoah (Redhat)
• ZGC (Oracle)
• Epsilon GC (experimental)

Redhat G1 presentation :

• https://www.redhat.com/en/blog/part-1-introduction-g1-garbage-collector
• https://www.redhat.com/en/blog/collecting-and-reading-g1-garbage-collector-logs-part-2

Zing JVM with C4 (Continuous Concurrent Compacting Collector) GC by AzulSystem https://www.azul.com/resources/azul-technology/azul-c4-garbage-collector/

Shenandoah GC (JEP 189) by RedHat

• https://wiki.openjdk.java.net/display/shenandoah/Main
• https://fr.slideshare.net/RedHatDevelopers/shenandoah-gc-java-without-the-garbage-collection-hiccups-christine-flood
• http://openjdk.java.net/jeps/189

ZGC by Oracle : A Scalable Low Latency Garbage Collector

• http://mail.openjdk.java.net/pipermail/announce/2017-October/000237.html
• https://fosdem.org/2018/schedule/event/zgc/attachments/slides/2211/export/events/attachments/zgc/slides/2211/ZGC_FOSDEM_2018.pdf
• https://www.infoworld.com/article/3235391/java/zgc-large-heap-java-garbage-collector-may-go-open-source.html

Epsilon GC : completely passive GC implementation with a bounded allocation limit and the lowest latency overhead possible

• http://openjdk.java.net/jeps/318
• https://www.infoq.com/news/2017/03/java-epsilon-gc