src/java.base/share/classes/sun/nio/ch/FileChannelImpl.java

*** 932,941 ****
--- 932,958 ----
      private static final int MAP_PV = 2;
  
      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");
          if (position < 0L)
              throw new IllegalArgumentException("Negative position");
*** 949,960 ****
          int imode = -1;
          if (mode == MapMode.READ_ONLY)
              imode = MAP_RO;
          else if (mode == MapMode.READ_WRITE)
              imode = MAP_RW;
!         else if (mode == MapMode.PRIVATE)
              imode = MAP_PV;
          assert (imode >= 0);
          if ((mode != MapMode.READ_ONLY) && !writable)
              throw new NonWritableChannelException();
          if (!readable)
              throw new NonReadableChannelException();
--- 966,978 ----
          int imode = -1;
          if (mode == MapMode.READ_ONLY)
              imode = MAP_RO;
          else if (mode == MapMode.READ_WRITE)
              imode = MAP_RW;
!         else if (mode == MapMode.PRIVATE) {
              imode = MAP_PV;
+         }
          assert (imode >= 0);
          if ((mode != MapMode.READ_ONLY) && !writable)
              throw new NonWritableChannelException();
          if (!readable)
              throw new NonReadableChannelException();
*** 993,1024 ****
                  if (size == 0) {
                      addr = 0;
                      // a valid file descriptor is not required
                      FileDescriptor dummy = new FileDescriptor();
                      if ((!writable) || (imode == MAP_RO))
!                         return Util.newMappedByteBufferR(0, 0, dummy, null);
                      else
!                         return Util.newMappedByteBuffer(0, 0, dummy, null);
                  }
  
                  pagePosition = (int)(position % allocationGranularity);
                  long mapPosition = position - pagePosition;
                  mapSize = size + pagePosition;
                  try {
                      // If map0 did not throw an exception, the address is valid
!                     addr = map0(imode, mapPosition, mapSize);
                  } catch (OutOfMemoryError x) {
                      // An OutOfMemoryError may indicate that we've exhausted
                      // memory so force gc and re-attempt map
                      System.gc();
                      try {
                          Thread.sleep(100);
                      } catch (InterruptedException y) {
                          Thread.currentThread().interrupt();
                      }
                      try {
!                         addr = map0(imode, mapPosition, mapSize);
                      } catch (OutOfMemoryError y) {
                          // After a second OOME, fail
                          throw new IOException("Map failed", y);
                      }
                  }
--- 1011,1042 ----
                  if (size == 0) {
                      addr = 0;
                      // a valid file descriptor is not required
                      FileDescriptor dummy = new FileDescriptor();
                      if ((!writable) || (imode == MAP_RO))
!                         return Util.newMappedByteBufferR(0, 0, dummy, null, isPersistent);
                      else
!                         return Util.newMappedByteBuffer(0, 0, dummy, null, isPersistent);
                  }
  
                  pagePosition = (int)(position % allocationGranularity);
                  long mapPosition = position - pagePosition;
                  mapSize = size + pagePosition;
                  try {
                      // If map0 did not throw an exception, the address is valid
!                     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
                      System.gc();
                      try {
                          Thread.sleep(100);
                      } catch (InterruptedException y) {
                          Thread.currentThread().interrupt();
                      }
                      try {
!                         addr = map0(imode, mapPosition, mapSize, isPersistent);
                      } catch (OutOfMemoryError y) {
                          // After a second OOME, fail
                          throw new IOException("Map failed", y);
                      }
                  }
*** 1040,1055 ****
              Unmapper um = new Unmapper(addr, mapSize, isize, mfd);
              if ((!writable) || (imode == MAP_RO)) {
                  return Util.newMappedByteBufferR(isize,
                                                   addr + pagePosition,
                                                   mfd,
!                                                  um);
              } else {
                  return Util.newMappedByteBuffer(isize,
                                                  addr + pagePosition,
                                                  mfd,
!                                                 um);
              }
          } finally {
              threads.remove(ti);
              endBlocking(IOStatus.checkAll(addr));
          }
--- 1058,1075 ----
              Unmapper um = new Unmapper(addr, mapSize, isize, mfd);
              if ((!writable) || (imode == MAP_RO)) {
                  return Util.newMappedByteBufferR(isize,
                                                   addr + pagePosition,
                                                   mfd,
!                                                  um,
!                                                  isPersistent);
              } else {
                  return Util.newMappedByteBuffer(isize,
                                                  addr + pagePosition,
                                                  mfd,
!                                                 um,
!                                                 isPersistent);
              }
          } finally {
              threads.remove(ti);
              endBlocking(IOStatus.checkAll(addr));
          }
*** 1199,1209 ****
      }
  
      // -- Native methods --
  
      // Creates a new mapping
!     private native long map0(int prot, long position, long length)
          throws IOException;
  
      // Removes an existing mapping
      private static native int unmap0(long address, long length);
  
--- 1219,1229 ----
      }
  
      // -- Native methods --
  
      // Creates a new mapping
!     private native long map0(int prot, long position, long length, boolean isPersistent)
          throws IOException;
  
      // Removes an existing mapping
      private static native int unmap0(long address, long length);