HotSwap

Patch name: hotswap.patch
Description: hotswap.txt

Implementation Notes

Thomas Wuerthinger, Dynamic Code Evolution for the Java HotSpotVirtual Machine

General Design Decisions

• Arbitrary changes possible (including changes to subtype relationships)
• No performance penalty before or after the change
• No introduced indirections
• Continued execution of old active methods
• Only simple, comprehensible strategies for field matching or method transitions

Status

• General mechanisms including the modifications to the garbage collector implemented, however still stability issues.
• Missing critical feature: Determine safety of type narrowing changes.
• Next step: Stabilize using the hotswapping test suite.