原文地址
hotspot/gc
1. Various GC combinations have now been removed
The GC combinations that were deprecated in JDK 8 have now been removed. This means that the following GC combinations no longer exist:
DefNew + CMS
ParNew + SerialOld
Incremental CMS The "foreground" mode for CMS has also been removed.
The command line flags that were removed are:
-Xincgc
-XX:+CMSIncrementalMode
-XX:+UseCMSCompactAtFullCollection
-XX:+CMSFullGCsBeforeCompaction
-XX:+UseCMSCollectionPassing
The command line flag -XX:+UseParNewGC no longer has any effect. ParNew can only be used with CMS and CMS requires ParNew. Thus, the -XX:+UseParNewGC flag has been deprecated and will likely be removed in a future release.
See JDK-8044022
hotspot/gc
2. Remove deprecated command line flags
These internal command line flags, which have been deprecated or aliased since JDK 6, have been removed:
CMSParPromoteBlocksToClaim
ParCMSPromoteBlocksToClaim
ParallelGCOldGenAllocBufferSize
ParallelGCToSpaceAllocBufferSize
UseGCTimeLimit
CMSPermGenSweepingEnabled
ResizeTLE
PrintTLE
TLESize
UseTLE
MaxTLERatio
TLEFragmentationRatio
TLEThreadRatio
In addition, these internal flags have been deprecated:
CMSMarkStackSizeMax
ParallelMarkingThreads
ParallelCMSThreads
CMSMarkStackSize
G1MarkStackSize
See JDK-8061611
hotspot/runtime
3. VM Options AdjustConcurrency and PrintJVMWarnings are removed
The VM Options -XX:AdjustConcurrency and -XX:PrintJVMWarnings are removed from JDK 9.
The VM option -XX:AdjustConcurrency was only needed on Solaris 8/9 (when using the T1 threading library).
The VM option -XX:PrintJVMWarnings was a development option only used by unimplemented VM functions that have themselves been removed in JDK 9.
See JDK-8073861
