JDK Enhancement Proposal 522 improves the throughput of Java's default garbage collector G1 by reducing contention and synchronization over an essential data structure called the _card table_. This leads to performance gains of anywhere between a few and up to 15%, depending on how heavily the application modifies object-reference fields. The more detailed version needs to explain some garbage collection basics, how a regional garbage collector works, what a card table and write barriers are, and how the just-in-time compiler is involved and all that before even getting to JEP 522.

JEP 522: https://openjdk.org/jeps/522
JDK 26: JDK 26: http://jdk.java.net/26

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JDK Enhancement Proposal (JEP) 522 improves the throughput of G1, Java's default garbage collector, by reducing contention and synchronization over the card table data structure. This yields performance gains of a few percent up to 15%, depending on how heavily an application modifies object-reference fields. A deeper technical breakdown covering GC basics, regional collectors, card tables, write barriers, and JIT compiler involvement is available in Inside Java Newscast #99.

Improved G1 Performance in #Java 26 #IJN #Coding