Gc – Inside.java

Garbage Collectors

2025

How ZGC Allocates Memory for the Java Heap by Joel Sikström on April 17, 2025
JDK 24 G1/Parallel/Serial GC Changes by Thomas Schatzl on April 7, 2025
New Write Barriers for G1 by Thomas Schatzl on April 2, 2025
Java 24 Release Notes Overview for Operations by Billy Korando on March 29, 2025
How Can Machine Learning Assist to Improve JVM Performance by Yagmur Eren on March 9, 2025
Garbage Collection in Java - The progress since JDK 8 by Stefan Johansson on February 15, 2025
Quality Outreach Heads-up - JDK 25: Proposal to Deprecate for Removal -UseCompressedClassPointers by Billy Korando on February 6, 2025
JVM Tuning with Machine Learning on Garbage Collection Logs by Yagmur Eren on January 13, 2025
Using Buddy Allocators to Reduce Inter-Page Fragmentation in ZGC by Casper Norrbin on January 8, 2025

2024

Mark–Scavenge: Waiting for Trash to Take Itself Out by Jonas Norlinder, Erik Österlund, Tobias Wrigstad David Black-Schaffer (guest) on November 22, 2024
ZGC Automatic Heap Sizing #JVMLS by Erik Österlund on November 9, 2024
JEP targeted to JDK 24: 490: ZGC: Remove the Non-Generational Mode by Axel Boldt-Christmas on November 1, 2024
JEP targeted to JDK 24: 475: Late Barrier Expansion for G1 by Roberto Castañeda Lozano, Erik Österlund on October 18, 2024
Java's Fraught Relationship with Cyclic Object Graphs by Stuart Marks on October 15, 2024
Project Lilliput - Beyond Compact Headers #JVMLS by Roman Kennke (guest) on September 6, 2024
JDK 23 G1/Parallel/Serial GC changes by Thomas Schatzl on July 24, 2024
Addressing Fragmentation in ZGC through Custom Allocators by Joel Sikström (guest) on June 19, 2024
JEP targeted to JDK 23: 474: ZGC: Generational Mode by Default by Axel Boldt-Christmas on May 7, 2024
JDK 22 in Two Minutes! - Sip of Java by Billy Korando on March 21, 2024
Netflix - Bending Pause Times to Your Will with Generational ZGC by Danny Thomas (guest) on March 6, 2024
When Should a Compiler Expand Garbage Collection Barriers? by Roberto Castañeda Lozano on February 16, 2024
JDK 22 G1/Parallel/Serial GC changes by Thomas Schatzl on February 9, 2024

2023

JDK 21: The GCs keep getting better by Stefan Johansson on December 14, 2023
Java 22 Unpacking - Inside Java Newscast #59 by Nicolai Parlog on December 7, 2023
JEP targeted to JDK 22: 423: Region Pinning for G1 by Hamlin Li (guest) on December 1, 2023
Introducing Generational ZGC by Billy Korando on November 28, 2023
Hazelcast Jet on Generational ZGC by Stefan Johansson on November 7, 2023
Reducing P99 Latencies with Generational ZGC by Stefan Johansson on October 21, 2023
G1: Java's Default Garbage Collector - Stack Walker #4 by Billy Korando on October 15, 2023
Generational ZGC - Sip of Java by Billy Korando on October 9, 2023
What is… a Concurrent Undo Cycle by Thomas Schatzl on October 4, 2023
Java 21 JVM and GC Improvements #RoadTo21 by Billy Korando on September 3, 2023
JVMLS - Generational ZGC and Beyond by Erik Österlund on August 31, 2023
G1/Parallel/Serial GC improvements in JDK 21 by Thomas Schatzl on August 10, 2023
Optimizing Memory Utilization with Automated Heap Sizing in ZGC by Marina Shimchenko (guest) on June 20, 2023
Preserving the Mental Map when Visualizing Dynamic Graphs by Emmy Yin (guest) on June 12, 2023
All That is in Java 21?! - Inside Java Newscast #50 by Nicolai Parlog on June 8, 2023
UseDynamicNumberOfCompilerThreads and Memory Footprint by Poonam Parhar on May 30, 2023
Save 10-20% Memory With Compact Headers - Inside Java Newscast #48 by Nicolai Parlog on May 11, 2023
JEP proposed to target JDK 21: 439: Generational ZGC by Stefan Karlsson on May 4, 2023
Z Garbage Collector: The Next Generation by Paul Su on April 23, 2023
Throughput Analysis of Safepoint-attached Barriers in a Low-latency Garbage Collector by Filip Wilén (guest) on April 3, 2023
G1/Parallel/Serial GC improvements in JDK 20 by Thomas Schatzl on March 17, 2023
ZGC : Java’s Highly Scalable Low-Latency Garbage Collector - Stack Walker #1 by Billy Korando on March 5, 2023
ZGC - The Future of Low-Latency Garbage Collection Is Here by Erik Österlund on January 25, 2023

2022

Quality Outreach Heads-up - New Generational ZGC Early Access Builds by Stefan Karlsson on November 29, 2022
Generational ZGC - Inside Java Newscast #37 by Billy Korando on November 17, 2022
Frequent Full GCs by Poonam Parhar on November 17, 2022
Generational ZGC Early-Access builds by Erik Österlund on October 18, 2022
G1/Parallel/Serial GC improvements in JDK 19 by Thomas Schatzl on September 21, 2022
G1 Pre-Barrier Implementation by Albert Yang on August 24, 2022
Concurrent Marking in G1 by Thomas Schatzl on August 18, 2022
The Serial Garbage Collector - Sip of Java by Billy Korando on August 8, 2022
The Parallel Garbage Collector - Sip of Java by Billy Korando on August 1, 2022
Mitigate the relocation degradations for cache locality improvement algorithm by Jinyu Yu (guest) on July 1, 2022
Episode 24 “Towards Generational ZGC!” by Erik Österlund, David Delabassee on June 29, 2022
The G1 Garbage Collector - Sip of Java by Billy Korando on June 20, 2022
JDK GCs Comparison - Sip of Java by Billy Korando on June 6, 2022
Concurrent Thread-stack Processing in the Z Garbage Collector by Erik Österlund on May 31, 2022
ZGC, the JDK's Newest Garbage Collector - Sip of Java by Billy Korando on May 30, 2022
JDK 8 to JDK 18 in Garbage Collection: 10 Releases, 2000+ Enhancements by Thomas Schatzl on May 2, 2022
ZGC - What's new in JDK 18 by Per Liden on April 29, 2022
ZGC - The Future of Low-Latency Garbage Collection Is Here by Per Liden on March 30, 2022
G1/Parallel/Serial GC improvements in JDK 18 by Thomas Schatzl on March 16, 2022
Card Table Card Size Shenanigans by Thomas Schatzl on February 16, 2022
New candidate JEP: 423: Region Pinning for G1 by Mark Reinhold on February 2, 2022

2021

Understanding Metaspace and Class Space GC Log Entries by Poonam Parhar on December 14, 2021
GC progress from JDK 8 to JDK 17 by Stefan Johansson on November 24, 2021
Heap Regions X-Large by Thomas Schatzl on November 15, 2021
G1: To Infinity and Beyond by Stefan Johansson on October 11, 2021
ZGC - What's new in JDK 17 by Per Liden on October 5, 2021
G1 GC & Parallel GC Improvements in JDK 17 by Thomas Schatzl on September 17, 2021
Large pages and Java by Stefan Johansson on May 19, 2021
ZGC - What's new in JDK 16 by Per Liden on March 22, 2021
G1 & Parallel GC Improvements in JDK 16 by Thomas Schatzl on March 15, 2021
Welcome 20% less memory usage for G1 remembered sets - Prune collection set candidates early by Thomas Schatzl on February 26, 2021

2020

NUMA-Aware Memory Allocation for G1 GC by Sangheon Kim on November 3, 2020
Episode 5 “The Z Garbage Collector (ZGC)” with Per Liden by Per Liden, David Delabassee on October 14, 2020
JEP proposed to target JDK 16: 376: ZGC: Concurrent Thread-Stack Processing by Mark Reinhold on September 24, 2020
ZGC - What's new in JDK 15 by Per Liden on September 22, 2020
ZGC: The Next Generation Low-Latency Garbage Collector by Per Liden on September 17, 2020
JEP proposed to target JDK 16: 387: Elastic Metaspace by Mark Reinhold on September 10, 2020
JDK 15 G1/Parallel GC changes by Thomas Schatzl on September 1, 2020
Heap Snapshotting by Thomas Schatzl & Ludvig Janiuk (guest) on May 12, 2025
New candidate JEP: 387: Elastic Metaspace by Mark Reinhold on July 7, 2020
ZGC - Using -XX:SoftMaxHeapSize by Per Liden on July 2, 2020
How do 'hot and cold' objects behave? by Per Liden & Hanna Nyblom (guest) on May 12, 2025
Compact Forwarding Information by Per Liden & Jonas Norlinder (guest) on May 12, 2025
Oracle, Uppsala University, and KTH in joint JVM research projects by Jesper Wilhelmsson on June 12, 2020
Improving G1 out-of-the-box performance by Stefan Johansson on April 16, 2020
ZGC - What's new in JDK 14 by Per Liden on March 23, 2020
Making ZGC Production Ready by Per Liden on February 20, 2020
HotSpot Handshaking by Robbin Ehn on February 10, 2020
G1: To infinity and beyond by Stefan Johansson on February 1, 2020

2019

A critical question, Zee GC or Zed GC? by Per Liden on October 4, 2019
ZGC and tmpfs/hugeltbfs by Per Liden on June 28, 2019
ZGC Concurrent Class Unloading by Erik Österlund on February 4, 2019

2018

The Z Garbage Collector by Erik Österlund on November 17, 2018
ZGC : A Scalable Low-Latency Garbage Collector by Per Liden on October 25, 2018

2017

Can young generation size impact response times? by Poonam Parhar on December 11, 2017