src/java.base/share/classes/java/nio/file/FileStore.java

*** 110,119 ****
--- 110,130 ----
       *          if an I/O error occurs
       */
      public abstract long getUsableSpace() throws IOException;
  
      /**
+      * Returns block size in Bytes to this Java virtual machine on the file
+      * store.
+      *
+      * @return  block size
+      *
+      * @throws IOException
+      *         if an I/O error occurs
+      */         
+     public abstract int getBlockSize() throws IOException;
+ 
+     /**
       * Returns the number of unallocated bytes in the file store.
       *
       * <p> The returned number of unallocated bytes is a hint, but not a
       * guarantee, that it is possible to use most or any of these bytes.  The
       * number of unallocated bytes is most likely to be accurate immediately