*** old/src/java.base/share/classes/jdk/internal/misc/Unsafe.java	Fri Feb  5 13:30:06 2016
--- new/src/java.base/share/classes/jdk/internal/misc/Unsafe.java	Fri Feb  5 13:30:06 2016

*** 456,479 ****
--- 456,522 ----
       */
      public void copyMemory(long srcAddress, long destAddress, long bytes) {
          copyMemory(null, srcAddress, null, destAddress, bytes);
      }
  
+     private boolean isPrimitiveArray(Class<?> c) {
+         Class<?> componentType = c.getComponentType();
+         return componentType != null && componentType.isPrimitive();
+     }
+ 
+     private native void copySwapMemory0(Object srcBase, long srcOffset,
+                                         Object destBase, long destOffset,
+                                         long bytes, long elemSize);
+         
+ 
      /**
-      * Copies all elements from one block of memory to another block, byte swapping the
!      * *unconditionally* byte swapping the elements on the fly.
       *
       * <p>This method determines each block's base address by means of two parameters,
       * and so it provides (in effect) a <em>double-register</em> addressing mode,
       * as discussed in {@link #getInt(Object,long)}.  When the object reference is null,
       * the offset supplies an absolute base address.
       *
       * @since 9
       */
-     public native void copySwapMemory(Object srcBase, long srcOffset,
                                 Object destBase, long destOffset,
                                        long bytes, long elemSize);
+                                long bytes, long elemSize) {
+         if (bytes < 0 || srcOffset < 0 || destOffset < 0) {
+             throw new IllegalArgumentException();
+         }
+         if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
+             throw new IllegalArgumentException();
+         }
+         if (bytes % elemSize != 0) {
+             throw new IllegalArgumentException();
+         }
+         if ((srcBase == null && srcOffset == 0) ||
+             (destBase == null && destOffset == 0)) {
+             throw new NullPointerException();
+         }
+ 
+         // Must be off-heap, or primitive heap arrays
+         if ((srcBase != null && !isPrimitiveArray(srcBase.getClass())) ||
+             (destBase != null && !isPrimitiveArray(destBase.getClass()))) {
+             throw new IllegalArgumentException();
+         }
+ 
+         // Sanity check size and offsets on 32-bit platforms. Most
+         // significant 32 bits must be zero.
+         if (ADDRESS_SIZE == 4 &&
+             (bytes >>> 32 != 0 || srcOffset >>> 32 != 0 || destOffset >>> 32 != 0)) {
+             throw new IllegalArgumentException();
+         }
+ 
+         if (bytes == 0) {
+             return;
+         }
+ 
+         copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
+     }
  
     /**
       * Copies all elements from one block of memory to another block, byte swapping the
       * elements on the fly.
       *