Java 21 (23.9 LTS)

Java 21 was released on 19th September 2023. This is an LTS release, two years after Java 17.

Status: General availability.

Resources

• https://jdk.java.net/21/release-notes

• https://jdk.java.net/21/

• Schedule, status and features

Selected changes targeted to Java 21

• JEP 439: Generational ZGC

• JEP 430: String Templates (Preview)

• JEP 431: Sequenced Collections

• https://openjdk.org/jeps/440

• https://openjdk.org/jeps/441

• https://openjdk.org/jeps/442

• https://openjdk.org/jeps/443

• https://openjdk.org/jeps/444

• https://openjdk.org/jeps/445

• https://openjdk.org/jeps/446

• https://openjdk.org/jeps/448

• https://openjdk.org/jeps/449

• https://openjdk.org/jeps/451

• https://openjdk.org/jeps/452

• https://openjdk.org/jeps/453

• New system property to toggle XML Signature secure validation mode (JDK-8301260)

• System.exit and Runtime.exit() Logging (JDK-8301627)

• https://bugs.openjdk.org/browse/JDK-8305972: Update XML Security for Java to 3.0.2

• https://bugs.openjdk.org/browse/JDK-8267140: Support closing the HttpClient by making it auto-closable

Summary of changes since Java 17 (previous LTS)

• https://openjdk.java.net/jeps/400

• https://openjdk.java.net/jeps/421

• JEP 431: Sequenced Collections

• https://openjdk.org/jeps/440

• https://openjdk.org/jeps/441

• https://openjdk.org/jeps/444