G1 Becomes the Default GC in JDK 27
JDK 27 G1/Parallel/Serial GC Changes
JDK 27 brings G1 as the default garbage collector across all environments, ending Serial GC's default status. The release includes over 350 GC changes, many focused on refactoring and bug fixes. Key improvements include better heap sizing after Full GC, adaptive concurrent marking, and fixes for humongous object reclamation. Parallel GC sees fixes to tenuring and heap expansion, while TLAB sizing and string deduplication logging improve across all collectors.
We thought that G1 fit the bill of a default collector nicely, and selecting something else depending on arcane environmental conditions was more of a burden than an advantage.