Java Objects Inside Out
summary
The talk examines Java object memory layout and footprint, explaining what fields and headers actually occupy in memory and how runtimes implement them. It covers how that knowledge clarifies object size tricks, runtime peculiarities, and what can be exploited for low-level or “dirty” purposes.
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chapters (16)
- 0:00Introduction
- 1:17Object measurement methodologies
- 8:37Memory analysis tool issues
- 12:31Java Object Layout tool
- 15:21Primitive type sizes in Java
- 18:52Boolean storage in memory
- 20:59Compressed oops in HotSpot
- 24:10Object header structure
- 27:44Markword: forwarding and object age
- 31:56Object hashCodes in HotSpot
- 38:16Locking and object header
- 42:51Class Word: role and structure
- 46:01Object alignment and effects
- 51:17Field packing and memory optimization
- 57:36Class hierarchy layout issues
- 1:03:16Summary
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