Java Development Kit (JDK) 24 is set to deliver 24 distinct features, including enhancements to structured concurrency and the introduction of quantum-resistant cryptographic mechanisms to safeguard applications against the future risks of quantum computing.

Current Development Phase

JDK 24 has reached its second rampdown phase, which signifies the feature set is now locked in. With the initial rampdown phase concluded on December 5, developers are now focused on resolving approved bugs. Two release candidates are expected in February, with the final production release scheduled for March 18, 2025. Compared to its predecessor, JDK 23, which included 12 features, JDK 24 offers twice the number of enhancements.

Key Additions

Recent features introduced include:

1. Runtime warnings for using memory-access methods in sun.misc.unsafe.
2. A fourth preview of structured concurrency.
3. The planned removal of the 32-bit x86 architecture support.
4. Quantum-resistant cryptography implementations such as module-lattice-based digital signature algorithms and key encapsulation mechanisms.

Noteworthy Enhancements

Earlier proposals for JDK 24 span a broad spectrum of improvements, including:

• Constructor Flexibility: New phases within constructors allow for cleaner and more intuitive object initialization.
• Ahead-of-Time Class Preparation: Optimizing startup performance through cached class loading and linking.
• Enhanced Virtual Thread Synchronization: Streamlining scalability by reducing platform thread pinning.
• Security Manager Removal: A move toward eliminating this outdated mechanism.
• Compact Object Headers: Reduced memory footprint for better performance on 64-bit architectures.
• Improved Pattern Matching: Expanded compatibility of primitive types with instanceof and switch constructs.

Quantum-Resistant Security

JDK 24 introduces cryptographic solutions to address the looming threat posed by quantum computing. Key features include:

• ML-KEM: A module-lattice-based key encapsulation mechanism for secure key exchange.
• ML-DSA: A digital signature algorithm designed to prevent tampering and verify identities in quantum-vulnerable environments.

Focus on Garbage Collection

The release continues advancements in memory management with updates like the Generational Shenandoah garbage collector. This experimental feature aims to enhance throughput and memory efficiency, with plans to make it the default in future releases.

Simplifying Programming

Java continues to evolve for beginners and seasoned developers alike. The fourth preview of simplified source files and instance main methods is designed to lower the barrier for newcomers while allowing the smooth integration of advanced concepts as they progress.

Looking Ahead

While JDK 24 is classified as a non-long-term support (LTS) release—offering only six months of premier support—it sets the stage for the upcoming JDK 25, the next LTS version slated for September 2025. Early builds of JDK 24 are currently available at jdk.java.net.