Optimizing JVM startup time is vital for many applications. This post explores various strategies, comparing their effectiveness through benchmarking a simple Netty server. Class Data Sharing (CDS) and its evolution, AppCDS, cache class data to reduce initialization overhead. By Michał Zyga.
This article then dives into the following:
- Caching class data (CDS/AppCDS) is a fundamental optimization
- AOT compilation (GraalVM) provides fast startup but has trade-offs
- Process snapshots (CRaC) can enable rapid restarts with potential for peak performance
- Project Leyden promises further improvements in startup speed
- Consider platform compatibility and application requirements when choosing a method
GraalVM leverages ahead-of-time compilation for faster startup but presents challenges with dynamic code and platform compatibility. CRaC uses process snapshots for rapid restarts, potentially maintaining peak performance but demanding code modifications and primarily supporting Linux. Project Leyden, still under development, aims to further accelerate startup by including more data in the archive. Benchmarks reveal that AppCDS offers a substantial improvement over CDS, while CRaC and GraalVM provide the fastest startup times. The best approach depends on factors like application complexity, desired performance level, and target platform. good read
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