--- old/src/java.base/share/classes/sun/nio/ch/FileChannelImpl.java	2018-07-19 11:59:00.932311536 +0100
+++ new/src/java.base/share/classes/sun/nio/ch/FileChannelImpl.java	2018-07-19 11:59:00.108309055 +0100
@@ -934,6 +934,23 @@
     public MappedByteBuffer map(MapMode mode, long position, long size)
         throws IOException
     {
+        return map_internal(mode, position, size, false);
+    }
+    
+    public MappedByteBuffer map_persistent(MapMode mode, long position, long size)
+        throws IOException
+    {
+        if (mode == MapMode.PRIVATE) {
+            throw new IllegalArgumentException("Mode private is not allowed for persistent_map");
+        }
+        return map_internal(mode, position, size, true);
+    }
+    
+    private MappedByteBuffer map_internal(MapMode mode,
+                                          long position, long size,
+                                          boolean isPersistent)
+        throws IOException
+    {
         ensureOpen();
         if (mode == null)
             throw new NullPointerException("Mode is null");
@@ -951,8 +968,9 @@
             imode = MAP_RO;
         else if (mode == MapMode.READ_WRITE)
             imode = MAP_RW;
-        else if (mode == MapMode.PRIVATE)
+        else if (mode == MapMode.PRIVATE) {
             imode = MAP_PV;
+        }
         assert (imode >= 0);
         if ((mode != MapMode.READ_ONLY) && !writable)
             throw new NonWritableChannelException();
@@ -995,9 +1013,9 @@
                     // a valid file descriptor is not required
                     FileDescriptor dummy = new FileDescriptor();
                     if ((!writable) || (imode == MAP_RO))
-                        return Util.newMappedByteBufferR(0, 0, dummy, null);
+                        return Util.newMappedByteBufferR(0, 0, dummy, null, isPersistent);
                     else
-                        return Util.newMappedByteBuffer(0, 0, dummy, null);
+                        return Util.newMappedByteBuffer(0, 0, dummy, null, isPersistent);
                 }
 
                 pagePosition = (int)(position % allocationGranularity);
@@ -1005,7 +1023,7 @@
                 mapSize = size + pagePosition;
                 try {
                     // If map0 did not throw an exception, the address is valid
-                    addr = map0(imode, mapPosition, mapSize);
+                    addr = map0(imode, mapPosition, mapSize, isPersistent);
                 } catch (OutOfMemoryError x) {
                     // An OutOfMemoryError may indicate that we've exhausted
                     // memory so force gc and re-attempt map
@@ -1016,7 +1034,7 @@
                         Thread.currentThread().interrupt();
                     }
                     try {
-                        addr = map0(imode, mapPosition, mapSize);
+                        addr = map0(imode, mapPosition, mapSize, isPersistent);
                     } catch (OutOfMemoryError y) {
                         // After a second OOME, fail
                         throw new IOException("Map failed", y);
@@ -1042,12 +1060,14 @@
                 return Util.newMappedByteBufferR(isize,
                                                  addr + pagePosition,
                                                  mfd,
-                                                 um);
+                                                 um,
+                                                 isPersistent);
             } else {
                 return Util.newMappedByteBuffer(isize,
                                                 addr + pagePosition,
                                                 mfd,
-                                                um);
+                                                um,
+                                                isPersistent);
             }
         } finally {
             threads.remove(ti);
@@ -1201,7 +1221,7 @@
     // -- Native methods --
 
     // Creates a new mapping
-    private native long map0(int prot, long position, long length)
+    private native long map0(int prot, long position, long length, boolean isPersistent)
         throws IOException;
 
     // Removes an existing mapping