The upcoming Java Development Kit (JDK) 24 introduces a host of updates aimed at improving functionality, performance, and security. Scheduled for release on March 18, 2025, this non-LTS version builds on its predecessor, JDK 23, by significantly expanding its feature set to include 24 proposals, with new advancements in concurrency, memory management, and quantum-resistant cryptography.

Highlights of JDK 24

1. Strengthened Memory Access Oversight

One of the latest updates introduces runtime warnings for methods within the sun.misc.Unsafe class, marking the first instance such a method is called. These methods, deprecated in JDK 23, have been replaced with safer alternatives in standard APIs. Designed for low-level memory operations, the Unsafe class was historically risky, and its gradual phase-out ensures a more secure and stable Java ecosystem.

2. Structured Concurrency (Fourth Preview)

Continuing its development, structured concurrency aims to simplify multithreaded programming by managing groups of related tasks as unified operations. This API enhances error handling and streamlines task cancellation, mitigating issues such as thread leaks and unintentional delays. These improvements are poised to make Java’s concurrent programming more reliable and easier to debug.

3. Transition Away from 32-bit x86 Support

JDK 24 takes another step toward deprecating 32-bit x86 architecture. Following the deprecation of the Windows 32-bit x86 port in earlier versions, this update marks the Linux 32-bit x86 port for removal as well. Once complete, the Zero port will be the only 32-bit option for Java applications, reflecting the declining relevance of 32-bit processors.

4. Quantum-Resistant Security Features

Java 24 introduces two critical quantum-resistant cryptographic algorithms:

• ML-KEM: A key encapsulation mechanism designed to secure symmetric keys over untrusted networks.
• ML-DSA: A digital signature algorithm that safeguards data integrity and authenticates identities.
  These features are part of Java’s ongoing efforts to future-proof its security against the potential risks posed by quantum computing.

Additional Enhancements

Flexible Constructor Bodies

Now in its third preview, this feature refines how constructors are used during object initialization. By introducing distinct phases for pre- and post-superclass initialization logic, developers gain more flexibility in structuring their code without relying on auxiliary methods.

Ahead-of-Time Class Loading

This update aims to accelerate application startup times by caching pre-loaded and linked class data for reuse in subsequent executions.

Improved Virtual Thread Management

Efforts to optimize virtual threads include changes that reduce thread pinning, allowing greater scalability by freeing platform threads when blocked.

Simplified Beginner Syntax

A fourth preview of streamlined source files and instance main methods further simplifies Java syntax, enabling newcomers to write basic programs without delving into advanced concepts.

Garbage Collection and Memory Optimization

• Generational Shenandoah introduces an experimental generational garbage collection mode, improving memory efficiency and handling load spikes.
• Removal of Non-Generational ZGC Mode consolidates development efforts by phasing out this outdated approach.
• Compact Object Headers reduce memory usage by shrinking object header sizes on 64-bit systems.

Other Significant Proposals

• Stream Gatherers expand the Stream API with new intermediate operations for enhanced data manipulation.
• Key Derivation Function (KDF) API introduces support for cryptographic key derivation methods like Argon2 and HMAC-based algorithms.
• Module Import Declarations simplify importing modular libraries, encouraging greater reuse without requiring module conversion.

Accessibility and Future Outlook

As a non-LTS release, JDK 24 will receive six months of premium support from Oracle. Developers eager to explore its features can access early builds at jdk.java.net. With its array of innovative features and performance improvements, JDK 24 marks a significant step forward in Java’s evolution, catering to modern development needs while addressing future challenges like quantum computing.