hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp

*** 786,801 ****
               && _survivor_chunk_array != NULL)
           || (   _survivor_chunk_capacity == 0
               && _survivor_chunk_index == 0),
           "Error");
  
!   // Choose what strong roots should be scanned depending on verification options
    if (!CMSClassUnloadingEnabled) {
      // If class unloading is disabled we want to include all classes into the root set.
      add_root_scanning_option(SharedHeap::SO_AllClasses);
-   } else {
-     add_root_scanning_option(SharedHeap::SO_SystemClasses);
    }
  
    NOT_PRODUCT(_overflow_counter = CMSMarkStackOverflowInterval;)
    _gc_counters = new CollectorCounters("CMS", 1);
    _completed_initialization = true;
--- 786,801 ----
               && _survivor_chunk_array != NULL)
           || (   _survivor_chunk_capacity == 0
               && _survivor_chunk_index == 0),
           "Error");
  
!   // Choose what strong roots should be scanned depending on verification options.
!   // If CMSClassUnloadingEnabled is on, root scanning option is set during
!   // setup_cms_unloading_and_verification_state() on each CMS cycle.
    if (!CMSClassUnloadingEnabled) {
      // If class unloading is disabled we want to include all classes into the root set.
      add_root_scanning_option(SharedHeap::SO_AllClasses);
    }
  
    NOT_PRODUCT(_overflow_counter = CMSMarkStackOverflowInterval;)
    _gc_counters = new CollectorCounters("CMS", 1);
    _completed_initialization = true;
*** 3308,3317 ****
--- 3308,3328 ----
  void CMSCollector::setup_cms_unloading_and_verification_state() {
    const  bool should_verify =   VerifyBeforeGC || VerifyAfterGC || VerifyDuringGC
                               || VerifyBeforeExit;
    const  int  rso           =   SharedHeap::SO_Strings | SharedHeap::SO_CodeCache;
  
+   // We set the proper root for this CMS cycle here.
+   // When class unloading is disabled, we set the default root scanning option
+   // once in the CMSCollector constructor.
+   if (CMSClassUnloadingEnabled) {
+     if (should_unload_classes()) {
+       set_root_scanning_option(SharedHeap::SO_SystemClasses);
+     } else {
+       set_root_scanning_option(SharedHeap::SO_AllClasses | rso);
+     }
+   }
+ 
    if (should_unload_classes()) {   // Should unload classes this cycle
      remove_root_scanning_option(rso);  // Shrink the root set appropriately
      set_verifying(should_verify);    // Set verification state for this cycle
      return;                            // Nothing else needs to be done at this time
    }