CDS (Class Data Sharing)

JVM Tutorials - Herong's Tutorial Examples

∟CDS (Class Data Sharing)

This chapter provides tutorial notes and example codes on CDS (Class Data Sharing). Topics include generating shared archive with HotSpot; saving startup time and footprint using shared archive; viewing shared memory of JVM processes.

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What Is Class Data Sharing

Regenerating Shared Archive

Startup Time Saving with Restoring Shared Archive

Startup Time Saving with Multiple JVM Processes

Footprint Saving with Restoring Shared Archive

Viewing Shared Memory of JVM Processes

Takeaways:

Class Data Sharing (CDS) is a feature introduced HotSpot JVM 1.5 to to reduce the startup time and footprint of JVM instances by using a shared archive of commonly used standard classes.
"-Xshare:dump" option can be used to regenerate the Shared Archive.
"-Xshare:off" option can be used to turn off the Class Data Sharing function. In this case all classes will be loaded normally.