--- old/src/java.base/share/classes/jdk/internal/jmod/JmodFile.java	2016-12-06 10:38:30.491480508 +0000
+++ new/src/java.base/share/classes/jdk/internal/jmod/JmodFile.java	2016-12-06 10:38:30.315484194 +0000
@@ -28,8 +28,10 @@
 import java.io.BufferedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.Iterator;
 import java.util.stream.Stream;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
@@ -39,9 +41,9 @@
  */
 public class JmodFile implements AutoCloseable {
     // jmod magic number and version number
-    public static final int JMOD_MAJOR_VERSION = 0x01;
-    public static final int JMOD_MINOR_VERSION = 0x00;
-    public static final byte[] JMOD_MAGIC_NUMBER = {
+    private static final int JMOD_MAJOR_VERSION = 0x01;
+    private static final int JMOD_MINOR_VERSION = 0x00;
+    private static final byte[] JMOD_MAGIC_NUMBER = {
         0x4A, 0x4D, /* JM */
         JMOD_MAJOR_VERSION, JMOD_MINOR_VERSION, /* version 1.0 */
     };
@@ -175,6 +177,10 @@
         this.zipfile = new ZipFile(file.toFile());
     }
 
+    public static void writeMagicNumber(OutputStream os) throws IOException {
+        os.write(JMOD_MAGIC_NUMBER);
+    }
+
     /**
      * Returns the {@code Entry} for a resource in a JMOD file section
      * or {@code null} if not found.