--- old/src/hotspot/share/gc/shenandoah/shenandoahRootProcessor.hpp	2019-06-11 20:26:22.253694838 -0400
+++ new/src/hotspot/share/gc/shenandoah/shenandoahRootProcessor.hpp	2019-06-11 20:26:21.743693932 -0400
@@ -61,9 +61,16 @@
   void oops_do(OopClosure* cl, uint worker_id);
 };
 
-class ShenandoahJNIHandleRoots : public ShenandoahSerialRoot {
+template <bool CONCURRENT = false>
+class ShenandoahJNIHandleRoots {
+private:
+  volatile bool _claimed;
+  OopStorage::ParState<CONCURRENT, false /* is_const */> _itr;
 public:
   ShenandoahJNIHandleRoots();
+
+  template <typename T>
+  void oops_do(T* cl, uint worker_id = 0);
 };
 
 class ShenandoahThreadRoots {
@@ -108,12 +115,14 @@
   void code_blobs_do(CodeBlobClosure* blob_cl, uint worker_id);
 };
 
+template <bool CONCURRENT = false>
 class ShenandoahClassLoaderDataRoots {
 public:
   ShenandoahClassLoaderDataRoots();
+  ~ShenandoahClassLoaderDataRoots();
 
-  void always_strong_cld_do(CLDClosure* clds, uint worker_id);
-  void cld_do(CLDClosure* clds, uint worker_id);
+  void always_strong_cld_do(CLDClosure* clds, uint worker_id = 0);
+  void cld_do(CLDClosure* clds, uint worker_id = 0);
 };
 
 class ShenandoahRootProcessor : public StackObj {
@@ -130,11 +139,11 @@
 template <typename ITR>
 class ShenandoahRootScanner : public ShenandoahRootProcessor {
 private:
-  ShenandoahSerialRoots          _serial_roots;
-  ShenandoahJNIHandleRoots       _jni_roots;
-  ShenandoahClassLoaderDataRoots _cld_roots;
-  ShenandoahThreadRoots          _thread_roots;
-  ShenandoahCodeCacheRoots<ITR>  _code_roots;
+  ShenandoahSerialRoots            _serial_roots;
+  ShenandoahJNIHandleRoots<>       _jni_roots;
+  ShenandoahClassLoaderDataRoots<> _cld_roots;
+  ShenandoahThreadRoots            _thread_roots;
+  ShenandoahCodeCacheRoots<ITR>    _code_roots;
 public:
   ShenandoahRootScanner(uint n_workers, ShenandoahPhaseTimings::Phase phase);
 
@@ -158,16 +167,17 @@
 // Evacuate all roots at a safepoint
 class ShenandoahRootEvacuator : public ShenandoahRootProcessor {
 private:
-  ShenandoahSerialRoots          _serial_roots;
-  ShenandoahJNIHandleRoots       _jni_roots;
-  ShenandoahClassLoaderDataRoots _cld_roots;
-  ShenandoahThreadRoots          _thread_roots;
-  ShenandoahWeakRoots            _weak_roots;
-  ShenandoahStringDedupRoots     _dedup_roots;
+  ShenandoahSerialRoots            _serial_roots;
+  ShenandoahJNIHandleRoots<>       _jni_roots;
+  ShenandoahClassLoaderDataRoots<> _cld_roots;
+  ShenandoahThreadRoots            _thread_roots;
+  ShenandoahWeakRoots              _weak_roots;
+  ShenandoahStringDedupRoots       _dedup_roots;
   ShenandoahCodeCacheRoots<ShenandoahCsetCodeRootsIterator> _code_roots;
+  bool                             _include_concurrent_roots;
 
 public:
-  ShenandoahRootEvacuator(uint n_workers, ShenandoahPhaseTimings::Phase phase);
+  ShenandoahRootEvacuator(uint n_workers, ShenandoahPhaseTimings::Phase phase, bool include_concurrent_roots);
 
   void roots_do(uint worker_id, OopClosure* oops);
 };
@@ -175,14 +185,14 @@
 // Update all roots at a safepoint
 class ShenandoahRootUpdater : public ShenandoahRootProcessor {
 private:
-  ShenandoahSerialRoots          _serial_roots;
-  ShenandoahJNIHandleRoots       _jni_roots;
-  ShenandoahClassLoaderDataRoots _cld_roots;
-  ShenandoahThreadRoots          _thread_roots;
-  ShenandoahWeakRoots            _weak_roots;
-  ShenandoahStringDedupRoots     _dedup_roots;
+  ShenandoahSerialRoots            _serial_roots;
+  ShenandoahJNIHandleRoots<>       _jni_roots;
+  ShenandoahClassLoaderDataRoots<> _cld_roots;
+  ShenandoahThreadRoots            _thread_roots;
+  ShenandoahWeakRoots              _weak_roots;
+  ShenandoahStringDedupRoots       _dedup_roots;
   ShenandoahCodeCacheRoots<ShenandoahCsetCodeRootsIterator> _code_roots;
-  const bool                     _update_code_cache;
+  const bool                       _update_code_cache;
 
 public:
   ShenandoahRootUpdater(uint n_workers, ShenandoahPhaseTimings::Phase phase, bool update_code_cache);
@@ -194,12 +204,12 @@
 // Adjuster all roots at a safepoint during full gc
 class ShenandoahRootAdjuster : public ShenandoahRootProcessor {
 private:
-  ShenandoahSerialRoots          _serial_roots;
-  ShenandoahJNIHandleRoots       _jni_roots;
-  ShenandoahClassLoaderDataRoots _cld_roots;
-  ShenandoahThreadRoots          _thread_roots;
-  ShenandoahWeakRoots            _weak_roots;
-  ShenandoahStringDedupRoots     _dedup_roots;
+  ShenandoahSerialRoots            _serial_roots;
+  ShenandoahJNIHandleRoots<>       _jni_roots;
+  ShenandoahClassLoaderDataRoots<> _cld_roots;
+  ShenandoahThreadRoots            _thread_roots;
+  ShenandoahWeakRoots              _weak_roots;
+  ShenandoahStringDedupRoots       _dedup_roots;
   ShenandoahCodeCacheRoots<ShenandoahAllCodeRootsIterator> _code_roots;
 
 public: