Java 27 Released with G1 as the Default Garbage Collector

Oracle released Java 27 with nine JEPs. G1 is now the default garbage collector in all environments, Compact Object Headers are enabled by default, and a hybrid post-quantum key exchange for TLS 1.3 is added. JDK 27 updates will be available until March 2027.

• G1 now selected by default if no collector is specified
• Compact Object Headers reduce object header from 96 to 64 bits
• Post-quantum key exchange for TLS 1.3 works without code changes
• JDK 27 support lasts until March 2027