--- a/src/share/vm/classfile/symbolTable.cpp	Tue Apr 07 11:20:51 2015 +0200
+++ b/src/share/vm/classfile/symbolTable.cpp	Tue Apr 07 14:58:49 2015 +0200
@@ -36,6 +36,7 @@
 #include "runtime/mutexLocker.hpp"
 #include "utilities/hashtable.inline.hpp"
 #if INCLUDE_ALL_GCS
+#include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
 #include "gc_implementation/g1/g1StringDedup.hpp"
 #endif
 
@@ -73,9 +74,9 @@
 void SymbolTable::initialize_symbols(int arena_alloc_size) {
   // Initialize the arena for global symbols, size passed in depends on CDS.
   if (arena_alloc_size == 0) {
-    _arena = new (mtSymbol) Arena();
+    _arena = new (mtSymbol) Arena(mtSymbol);
   } else {
-    _arena = new (mtSymbol) Arena(arena_alloc_size);
+    _arena = new (mtSymbol) Arena(mtSymbol, arena_alloc_size);
   }
 }
 
@@ -204,7 +205,7 @@
     }
   }
   // If the bucket size is too deep check if this hash code is insufficient.
-  if (count >= BasicHashtable<mtSymbol>::rehash_count && !needs_rehashing()) {
+  if (count >= rehash_count && !needs_rehashing()) {
     _needs_rehashing = check_rehash_table(count);
   }
   return NULL;
@@ -655,7 +656,7 @@
     }
   }
   // If the bucket size is too deep check if this hash code is insufficient.
-  if (count >= BasicHashtable<mtSymbol>::rehash_count && !needs_rehashing()) {
+  if (count >= rehash_count && !needs_rehashing()) {
     _needs_rehashing = check_rehash_table(count);
   }
   return NULL;
@@ -704,11 +705,26 @@
   return lookup(chars, length);
 }
 
+// Tell the GC that this string was looked up in the StringTable.
+static void ensure_string_alive(oop string) {
+  // A lookup in the StringTable could return an object that was previously
+  // considered dead. The SATB part of G1 needs to get notified about this
+  // potential resurrection, otherwise the marking might not find the object.
+#if INCLUDE_ALL_GCS
+  if (UseG1GC && string != NULL) {
+    G1SATBCardTableModRefBS::enqueue(string);
+  }
+#endif
+}
 
 oop StringTable::lookup(jchar* name, int len) {
   unsigned int hash = hash_string(name, len);
   int index = the_table()->hash_to_index(hash);
-  return the_table()->lookup(index, name, len, hash);
+  oop string = the_table()->lookup(index, name, len, hash);
+
+  ensure_string_alive(string);
+
+  return string;
 }
 
 
@@ -719,7 +735,10 @@
   oop found_string = the_table()->lookup(index, name, len, hashValue);
 
   // Found
-  if (found_string != NULL) return found_string;
+  if (found_string != NULL) {
+    ensure_string_alive(found_string);
+    return found_string;
+  }
 
   debug_only(StableMemoryChecker smc(name, len * sizeof(name[0])));
   assert(!Universe::heap()->is_in_reserved(name),
@@ -744,11 +763,17 @@
 
   // Grab the StringTable_lock before getting the_table() because it could
   // change at safepoint.
-  MutexLocker ml(StringTable_lock, THREAD);
+  oop added_or_found;
+  {
+    MutexLocker ml(StringTable_lock, THREAD);
+    // Otherwise, add to symbol to table
+    added_or_found = the_table()->basic_add(index, string, name, len,
+                                  hashValue, CHECK_NULL);
+  }
 
-  // Otherwise, add to symbol to table
-  return the_table()->basic_add(index, string, name, len,
-                                hashValue, CHECK_NULL);
+  ensure_string_alive(added_or_found);
+
+  return added_or_found;
 }
 
 oop StringTable::intern(Symbol* symbol, TRAPS) {