JDK-8170636 : Release Note: Use Unified Logging for GC logging
  • Type: Sub-task
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 9
  • Priority: P4
  • Status: Closed
  • Resolution: Delivered
  • Submitted: 2016-12-02
  • Updated: 2017-09-22
  • Resolved: 2017-04-06
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JDK 9
9Resolved
Description
The logging for all garbage collectors in HotSpot have been changed to make use of a new logging framework that is configured through the `-Xlog` command line option. The command line flags `-XX:+PrintGC, -XX:+PrintGCDetails` and `-Xloggc` have been deprecated and will likely be removed in a future release. They are currently mapped to similar `-Xlog` configurations. 
All other flags that were used to control garbage collection logging have been removed. See the documentation for `-Xlog` for details on how to now configure and control the logging. These are the flags that were removed: 

`CMSDumpAtPromotionFailure`, `CMSPrintEdenSurvivorChunks`, `G1LogLevel`, `G1PrintHeapRegions`, `G1PrintRegionLivenessInfo`, `G1SummarizeConcMark`, `G1SummarizeRSetStats`, `G1TraceConcRefinement`, `G1TraceEagerReclaimHumongousObjects`, `G1TraceStringSymbolTableScrubbing`, `GCLogFileSize`, `NumberOfGCLogFiles`, `PrintAdaptiveSizePolicy`, `PrintClassHistogramAfterFullGC`, `PrintClassHistogramBeforeFullGC`, `PrintCMSInitiationStatistics`, `PrintCMSStatistics`, `PrintFLSCensus`, `PrintFLSStatistics`, `PrintGCApplicationConcurrentTime`, `PrintGCApplicationStoppedTime`, `PrintGCCause`, `PrintGCDateStamps`, `PrintGCID`, `PrintGCTaskTimeStamps`, `PrintGCTimeStamps`, `PrintHeapAtGC`, `PrintHeapAtGCExtended`, `PrintJNIGCStalls`, `PrintOldPLAB`, `PrintParallelOldGCPhaseTimes`, `PrintPLAB`, `PrintPromotionFailure`, `PrintReferenceGC`, `PrintStringDeduplicationStatistics`, `PrintTaskqueue`, `PrintTenuringDistribution`, `PrintTerminationStats`, `PrintTLAB`, `TraceDynamicGCThreads`, `TraceMetadataHumongousAllocation`, `UseGCLogFileRotation`, `VerifySilently`
Comments
This release note is based on the information used for the docs described in: https://bugs.openjdk.java.net/browse/JDK-8152173 For the docs we use links to make it easy to find the documentation, will this be the case for the release note as well or should we include that: -XX:+PrintGC ~ -Xlog:gc -XX:+PrintGCDetails ~-Xlog:gc* -Xloggc:log.out ~ -Xlog:gc:log.out
24-03-2017