1 files changed, 40 insertions, 26 deletions

diff --git a/luni/src/main/java/java/util/concurrent/ConcurrentLinkedQueue.java b/luni/src/main/java/java/util/concurrent/ConcurrentLinkedQueue.java
index 3ed0a7c..a0a26fd 100644
--- a/luni/src/main/java/java/util/concurrent/ConcurrentLinkedQueue.java
+++ b/luni/src/main/java/java/util/concurrent/ConcurrentLinkedQueue.java
@@ -1,7 +1,7 @@
 /*
  * Written by Doug Lea and Martin Buchholz with assistance from members of
  * JCP JSR-166 Expert Group and released to the public domain, as explained
- * at http://creativecommons.org/licenses/publicdomain
+ * at http://creativecommons.org/publicdomain/zero/1.0/
  */
 
 package java.util.concurrent;
@@ -47,7 +47,14 @@ import java.util.Queue;
  * <p>Beware that, unlike in most collections, the {@code size} method
  * is <em>NOT</em> a constant-time operation. Because of the
  * asynchronous nature of these queues, determining the current number
- * of elements requires a traversal of the elements.
+ * of elements requires a traversal of the elements, and so may report
+ * inaccurate results if this collection is modified during traversal.
+ * Additionally, the bulk operations {@code addAll},
+ * {@code removeAll}, {@code retainAll}, {@code containsAll},
+ * {@code equals}, and {@code toArray} are <em>not</em> guaranteed
+ * to be performed atomically. For example, an iterator operating
+ * concurrently with an {@code addAll} operation might view only some
+ * of the added elements.
  *
  * <p>This class and its iterator implement all of the <em>optional</em>
  * methods of the {@link Queue} and {@link Iterator} interfaces.
@@ -165,12 +172,22 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
 
         // Unsafe mechanics
 
-        private static final sun.misc.Unsafe UNSAFE =
-            sun.misc.Unsafe.getUnsafe();
-        private static final long nextOffset =
-            objectFieldOffset(UNSAFE, "next", Node.class);
-        private static final long itemOffset =
-            objectFieldOffset(UNSAFE, "item", Node.class);
+        private static final sun.misc.Unsafe UNSAFE;
+        private static final long itemOffset;
+        private static final long nextOffset;
+
+        static {
+            try {
+                UNSAFE = sun.misc.Unsafe.getUnsafe();
+                Class<?> k = Node.class;
+                itemOffset = UNSAFE.objectFieldOffset
+                    (k.getDeclaredField("item"));
+                nextOffset = UNSAFE.objectFieldOffset
+                    (k.getDeclaredField("next"));
+            } catch (Exception e) {
+                throw new Error(e);
+            }
+        }
     }
 
     /**
@@ -563,8 +580,7 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
      * The following code can be used to dump the queue into a newly
      * allocated array of {@code String}:
      *
-     * <pre>
-     *     String[] y = x.toArray(new String[0]);</pre>
+     *  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
      *
      * Note that {@code toArray(new Object[0])} is identical in function to
      * {@code toArray()}.
@@ -761,14 +777,6 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
             throw new NullPointerException();
     }
 
-    // Unsafe mechanics
-
-    private static final sun.misc.Unsafe UNSAFE = sun.misc.Unsafe.getUnsafe();
-    private static final long headOffset =
-        objectFieldOffset(UNSAFE, "head", ConcurrentLinkedQueue.class);
-    private static final long tailOffset =
-        objectFieldOffset(UNSAFE, "tail", ConcurrentLinkedQueue.class);
-
     private boolean casTail(Node<E> cmp, Node<E> val) {
         return UNSAFE.compareAndSwapObject(this, tailOffset, cmp, val);
     }
@@ -777,15 +785,21 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
         return UNSAFE.compareAndSwapObject(this, headOffset, cmp, val);
     }
 
-    static long objectFieldOffset(sun.misc.Unsafe UNSAFE,
-                                  String field, Class<?> klazz) {
+    // Unsafe mechanics
+
+    private static final sun.misc.Unsafe UNSAFE;
+    private static final long headOffset;
+    private static final long tailOffset;
+    static {
         try {
-            return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
-        } catch (NoSuchFieldException e) {
-            // Convert Exception to corresponding Error
-            NoSuchFieldError error = new NoSuchFieldError(field);
-            error.initCause(e);
-            throw error;
+            UNSAFE = sun.misc.Unsafe.getUnsafe();
+            Class<?> k = ConcurrentLinkedQueue.class;
+            headOffset = UNSAFE.objectFieldOffset
+                (k.getDeclaredField("head"));
+            tailOffset = UNSAFE.objectFieldOffset
+                (k.getDeclaredField("tail"));
+        } catch (Exception e) {
+            throw new Error(e);
         }
     }
 }