--- old/src/jdk.jartool/share/classes/sun/tools/jar/Main.java	2017-03-14 15:10:08.000000000 +0000
+++ new/src/jdk.jartool/share/classes/sun/tools/jar/Main.java	2017-03-14 15:10:08.000000000 +0000
@@ -26,19 +26,12 @@
 package sun.tools.jar;
 
 import java.io.*;
-import java.lang.module.Configuration;
-import java.lang.module.InvalidModuleDescriptorException;
-import java.lang.module.ModuleDescriptor;
+import java.lang.module.*;
 import java.lang.module.ModuleDescriptor.Exports;
 import java.lang.module.ModuleDescriptor.Provides;
 import java.lang.module.ModuleDescriptor.Opens;
 import java.lang.module.ModuleDescriptor.Requires;
 import java.lang.module.ModuleDescriptor.Version;
-import java.lang.module.ModuleFinder;
-import java.lang.module.ModuleReader;
-import java.lang.module.ModuleReference;
-import java.lang.module.ResolutionException;
-import java.lang.module.ResolvedModule;
 import java.net.URI;
 import java.nio.ByteBuffer;
 import java.nio.file.Path;
@@ -408,7 +401,7 @@
                 boolean found;
                 if (fname != null) {
                     try (ZipFile zf = new ZipFile(fname)) {
-                        found = printModuleDescriptor(zf);
+                        found = describeModule(zf);
                     }
                 } else {
                     try (FileInputStream fin = new FileInputStream(FileDescriptor.in)) {
@@ -604,7 +597,7 @@
         int n = args.length - count;
         if (n > 0) {
             if (dflag) {
-                // "--print-module-descriptor/-d" does not require file argument(s)
+                // "--describe-module/-d" does not require file argument(s)
                 usageError(formatMsg("error.bad.dflag", args[count]));
                 return false;
             }
@@ -1729,18 +1722,34 @@
                            .collect(joining(", ", prefix, suffix));
     }
 
-    private boolean printModuleDescriptor(ZipFile zipFile)
-        throws IOException
-    {
+    private boolean describeModule(ZipFile zipFile) throws IOException {
         ZipEntry[] zes = zipFile.stream()
             .filter(e -> isModuleInfoEntry(e.getName()))
             .sorted(Validator.ENTRY_COMPARATOR)
             .toArray(ZipEntry[]::new);
-        if (zes.length == 0)
-            return false;
-        for (ZipEntry ze : zes) {
-            try (InputStream is = zipFile.getInputStream(ze)) {
-                printModuleDescriptor(is, ze.getName());
+
+        if (zes.length == 0) {
+            // No module descriptor found, derive the automatic module name
+            String fn = zipFile.getName();
+            ModuleFinder mf = ModuleFinder.of(Paths.get(fn));
+            try {
+                Set<ModuleReference> mref = mf.findAll();
+                if (mref.size() != 1)
+                    fatalError(formatMsg("error.expected.find.module", fn));
+                String nv = mref.iterator().next().descriptor().toNameAndVersion();
+                output(formatMsg("out.automodule.name", nv));
+            } catch (FindException e) {
+                String msg = formatMsg("error.unable.derive.automodule", fn);
+                Throwable t = e.getCause();
+                if (t != null)
+                    msg = msg + "\n" + t.getMessage();
+                output(msg);
+            }
+        } else {
+            for (ZipEntry ze : zes) {
+                try (InputStream is = zipFile.getInputStream(ze)) {
+                    printModuleDescriptor(is, ze.getName());
+                }
             }
         }
         return true;