--- old/src/java.base/share/classes/jdk/internal/jrtfs/JrtPath.java	2017-12-22 15:05:51.000000000 -0800
+++ new/src/java.base/share/classes/jdk/internal/jrtfs/JrtPath.java	2017-12-22 15:05:50.000000000 -0800
@@ -45,6 +45,7 @@
 import java.util.Set;
 import static java.nio.file.StandardOpenOption.*;
 import static java.nio.file.StandardCopyOption.*;
+import jdk.internal.io.IOSupport;
 
 /**
  * Base class for Path implementation of jrt file systems.
@@ -793,11 +794,7 @@
         } else {
             try (InputStream is = jrtfs.newInputStream(this);
                  OutputStream os = target.newOutputStream()) {
-                byte[] buf = new byte[8192];
-                int n;
-                while ((n = is.read(buf)) != -1) {
-                    os.write(buf, 0, n);
-                }
+                IOSupport.copy(is, os);
             }
         }
         if (copyAttrs) {