Java Development Kit (JDK) 25: A Glimpse at the Latest Features
Scheduled for release in September, JDK 25 is shaping up to be an important long-term support (LTS) version of Java, bringing new features and significant changes. Two of the most notable updates already proposed for this release include the introduction of a preview API for stable values and the removal of the long-deprecated 32-bit x86 port. These updates aim to enhance performance, improve efficiency, and streamline the Java ecosystem for developers.
Stable Values: A Boost for Java Application Startup
One of the standout features of JDK 25 is the preview API for stable values. This introduces a new class of objects designed to hold immutable data, which can be treated like constants by the Java Virtual Machine (JVM). By optimizing how these stable values are initialized, the new feature targets a faster startup time for Java applications. Unlike traditional final fields, stable values provide more flexibility in terms of initialization timing, without compromising performance. This allows Java applications to break down monolithic initialization processes, leading to more efficient execution, especially in multi-threaded environments.
The Impact of Stable Values on Performance and Thread Safety
The proposal for stable values isn’t just about startup speed—it also offers performance benefits across the board. With stable values, Java code can now safely leverage constant-folding optimizations, a feature that was previously limited to JDK internals. Moreover, stable values are guaranteed to be initialized at most once, even in complex, multi-threaded environments. This ensures thread safety without the need for costly synchronization mechanisms. The ability to decouple creation and initialization of stable values further aids in reducing initialization time and boosts overall performance in Java applications.
Removal of the 32-bit x86 Port: Streamlining Java’s Future
JDK 25 also marks a significant shift with the proposed removal of the 32-bit x86 port, which has been deprecated since JDK 24. This decision stems from the growing cost of maintaining this port, which has increasingly become a burden for the development of newer features. The removal aligns with Oracle’s strategy to focus resources on more modern architectures, ensuring that features like the foreign function memory API can be better supported and enhanced. By eliminating the 32-bit x86 port, OpenJDK developers can accelerate the evolution of Java, allowing for more innovation and focus on forward-looking features, rather than backward compatibility with outdated systems.