Java JEP 483: Ahead-of-Time Class Loading & Linking Boosts Startup Time

2024-12-22

JEP 483 significantly improves Java application startup time by loading and linking application classes ahead of time when the HotSpot JVM starts. It achieves this by monitoring a single application run, storing the loaded and linked forms of all classes in a cache for reuse in subsequent runs. This feature requires no code changes and offers substantial speed improvements for large server applications, such as Spring PetClinic showing a 42% reduction in startup time. While currently a two-step process, future versions will streamline cache creation to a single step and offer more flexible training run configuration.

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