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JavaZone 2019: Garbage Collectors for busy Java developers

Ef619c225f56f02cc6ef1431e28b1977?s=47 Marco Molteni
September 12, 2019

JavaZone 2019: Garbage Collectors for busy Java developers

Which Garbage collectors save you more money in the Cloud? What's the difference between a Serial and a Parallel GC? What is Shenandoah and why is so good? Do you know which GC you are using daily?
A quick visual overview on the Java Garbage collectors, the GC will be explained in plain English without Statistical formulas.

Ef619c225f56f02cc6ef1431e28b1977?s=128

Marco Molteni

September 12, 2019
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  1. Marco Molteni

  2. 3 7

  3. Supported Experimental Deprecated (but included) G1 Z Shenandoah Epsilon Non-

    concurrent Concurrent No-ops Java 8 Serial Parallel Java 12 CMS 4 7
  4. Supported Experimental Deprecated (but included) G1 Z Shenandoah Epsilon Non-

    concurrent Concurrent No-ops Java 8 Serial Parallel Java 12 CMS 4 3
  5. None
  6. No collector satisfies every requirement Vertically scalable High throughput Low

    latency Low footprint
  7. None
  8. App Thread App Thread GC Thread Pause GC Thread App

    Thread App Thread App Thread Pause Pause
  9. High Throughput Low footprint Scalable Low latency Non-Concurrent (Parallel, Serial)

    Concurrent (G1, Shenandoah, Z)
  10. None
  11. Parallel GC App Thread GC Serial App Thread Serverless functions.

    Microdevices. Batch jobs.
  12. None
  13. Parallel Serial G1 Z Shenandoah

  14. Java 9 JEP 248: Make G1 the Default Garbage Collector

  15. Ultra-short pauses (<10 ms). Scalable to TB of heap. Experimental.

  16. Red Hat Oracle Lead Platforms Production ready Platform independent Linux

    only Java 8u, 11u only RedHat builds Experimental only
  17. None
  18. Shenandoah G1 & Serial Parallel Z (Java 13) Allocated Heap

    Used Heap
  19. No GC activities. Great for tests. Epsilon

  20. Man kan ikke få både i pose og sekk Garbage

    Collectors = Tradeoff. The best collector is the one that works the well for YOUR application, not the one suggested in Stack Overflow / benchmarks.