--- a/src/jdk.jpackage/share/classes/jdk/jpackage/internal/AbstractImageBundler.java	Fri May 31 08:26:31 2019 -0400
+++ b/src/jdk.jpackage/share/classes/jdk/jpackage/internal/AbstractImageBundler.java	Thu Jun 06 19:07:18 2019 -0400
@@ -128,6 +128,11 @@
                     name, outputDirectory.getAbsolutePath()));
         }
 
+        // NAME will default to CLASS, so the real problem is no MAIN_CLASS
+        if (name == null) {
+            throw new PackagerException("ERR_NoMainClass");
+        }
+
         // Create directory structure
         File rootDirectory = new File(outputDirectory, name);
 

--- a/src/jdk.jpackage/share/classes/jdk/jpackage/internal/JLinkBundlerHelper.java	Fri May 31 08:26:31 2019 -0400
+++ b/src/jdk.jpackage/share/classes/jdk/jpackage/internal/JLinkBundlerHelper.java	Thu Jun 06 19:07:18 2019 -0400
@@ -182,6 +182,12 @@
     static void execute(Map<String, ? super Object> params,
             AbstractAppImageBuilder imageBuilder)
             throws IOException, Exception {
+
+        // we might be able to build it (with no main class) but it won't run
+        if (StandardBundlerParam.MAIN_CLASS.fetchFrom(params) == null) {
+            throw new PackagerException("ERR_NoMainClass");
+        }
+
         List<Path> modulePath =
                 StandardBundlerParam.MODULE_PATH.fetchFrom(params);
         Set<String> addModules =

--- a/src/jdk.jpackage/share/classes/jdk/jpackage/internal/StandardBundlerParam.java	Fri May 31 08:26:31 2019 -0400
+++ b/src/jdk.jpackage/share/classes/jdk/jpackage/internal/StandardBundlerParam.java	Thu Jun 06 19:07:18 2019 -0400
@@ -161,6 +161,9 @@
                                 BundleParams.PARAM_APPLICATION_CLASS);
                         if (s == null) {
                             s = JLinkBundlerHelper.getMainClass(params);
+                            if (s.length() == 0) {
+                                s = null;
+                            }
                         }
                         return s;
                     },

--- a/src/jdk.jpackage/share/classes/jdk/jpackage/internal/resources/MainResources.properties	Fri May 31 08:26:31 2019 -0400
+++ b/src/jdk.jpackage/share/classes/jdk/jpackage/internal/resources/MainResources.properties	Thu Jun 06 19:07:18 2019 -0400
@@ -47,8 +47,6 @@
 error.cannot-create-output-dir=Output directory {0} cannot be created.
 error.cannot-write-to-output-dir=Output directory {0} is not writable.
 error.root-exists=Error: Application output directory {0} already exists.
-error.no-application-class=Main application class is missing.
-error.no-application-class.advice=Please specify main application class.
 error.no-main-class-with-main-jar=A main class was not specified nor was one found in the jar {0}.
 error.no-main-class-with-main-jar.advice=Specify a main class or ensure that the jar {0} specifies one in the manifest.
 error.no-main-class=A main class was not specified nor was one found in the supplied application resources.
@@ -69,8 +67,7 @@
 MSG_Version=jpackage version
 MSG_BundlerFailed=Error: Bundler "{1}" ({0}) failed to produce a bundle.
 
-
-
+ERR_NoMainClass=Error: Main application class is missing.
 ERR_UnsupportedOption=Error: Option [{0}] is not valid on this platform.
 ERR_NotImageOption=Error: Option [{0}] is not valid in create-app-image mode.
 ERR_NotInstallerOption=Error: Option [{0}] is not valid with --app-image option.

--- a/src/jdk.jpackage/share/classes/jdk/jpackage/internal/resources/MainResources_ja.properties	Fri May 31 08:26:31 2019 -0400
+++ b/src/jdk.jpackage/share/classes/jdk/jpackage/internal/resources/MainResources_ja.properties	Thu Jun 06 19:07:18 2019 -0400
@@ -47,8 +47,6 @@
 error.cannot-create-output-dir=Output directory {0} cannot be created.
 error.cannot-write-to-output-dir=Output directory {0} is not writable.
 error.root-exists=Error: Application output directory {0} already exists.
-error.no-application-class=Main application class is missing.
-error.no-application-class.advice=Please specify main application class.
 error.no-main-class-with-main-jar=A main class was not specified nor was one found in the jar {0}.
 error.no-main-class-with-main-jar.advice=Specify a main class or ensure that the jar {0} specifies one in the manifest.
 error.no-main-class=A main class was not specified nor was one found in the supplied application resources.
@@ -69,8 +67,7 @@
 MSG_Version=jpackage version
 MSG_BundlerFailed=Error: Bundler "{1}" ({0}) failed to produce a bundle.
 
-
-
+ERR_NoMainClass=Error: Main application class is missing.
 ERR_UnsupportedOption=Error: Option [{0}] is not valid on this platform.
 ERR_NotImageOption=Error: Option [{0}] is not valid in create-app-image mode.
 ERR_NotInstallerOption=Error: Option [{0}] is not valid with --app-image option.

--- a/src/jdk.jpackage/share/classes/jdk/jpackage/internal/resources/MainResources_zh_CN.properties	Fri May 31 08:26:31 2019 -0400
+++ b/src/jdk.jpackage/share/classes/jdk/jpackage/internal/resources/MainResources_zh_CN.properties	Thu Jun 06 19:07:18 2019 -0400
@@ -47,8 +47,6 @@
 error.cannot-create-output-dir=Output directory {0} cannot be created.
 error.cannot-write-to-output-dir=Output directory {0} is not writable.
 error.root-exists=Error: Application output directory {0} already exists.
-error.no-application-class=Main application class is missing.
-error.no-application-class.advice=Please specify main application class.
 error.no-main-class-with-main-jar=A main class was not specified nor was one found in the jar {0}.
 error.no-main-class-with-main-jar.advice=Specify a main class or ensure that the jar {0} specifies one in the manifest.
 error.no-main-class=A main class was not specified nor was one found in the supplied application resources.
@@ -69,8 +67,7 @@
 MSG_Version=jpackage version
 MSG_BundlerFailed=Error: Bundler "{1}" ({0}) failed to produce a bundle.
 
-
-
+ERR_NoMainClass=Error: Main application class is missing.
 ERR_UnsupportedOption=Error: Option [{0}] is not valid on this platform.
 ERR_NotImageOption=Error: Option [{0}] is not valid in create-app-image mode.
 ERR_NotInstallerOption=Error: Option [{0}] is not valid with --app-image option.

--- a/test/jdk/tools/jpackage/createappimage/JPackageCreateAppImageModuleMainClassErrorTest.java	Fri May 31 08:26:31 2019 -0400
+++ b/test/jdk/tools/jpackage/createappimage/JPackageCreateAppImageModuleMainClassErrorTest.java	Thu Jun 06 19:07:18 2019 -0400
@@ -39,20 +39,27 @@
     private static final String appOutput = JPackagePath.getAppOutputFile();
     private static final String appWorkingDir = JPackagePath.getAppWorkingDir();
 
-    private static final String [] CMD = {
+    private static final String [] CMD1 = {
         "create-app-image",
         "--output", OUTPUT,
         "--name", "test",
         "--module", "com.hello",
         "--module-path", "input"};
 
+    private static final String [] CMD2 = {
+        "create-app-image",
+        "--output", OUTPUT,
+        "--name", "test",
+        "--module", "com.hello/com.hello.Hello",
+        "--module-path", "input"};
+
     private static void validate(String buildOutput) throws Exception {
 
         File outfile = new File(appWorkingDir + File.separator + appOutput);
         int retVal = JPackageHelper.execute(outfile, app);
-        if (retVal == 0) {
+        if (retVal != 0) {
             throw new AssertionError(
-                   "Test application exited without error: ");
+                   "Test application exited with error: ");
         }
 
         if (!outfile.exists()) {
@@ -61,15 +68,12 @@
         String output = Files.readString(outfile.toPath());
         String[] result = output.split("\n");
 
-        if (result.length != 1) {
-            System.out.println("outfile (" + outfile + ") content: " + output);
-            throw new AssertionError(
-                   "Unexpected number of lines: " + result.length);
+        if (!result[0].trim().equals("jpackage test application")) {
+            throw new AssertionError("Unexpected result[0]: " + result[0]);
         }
 
-        if (!result[0].trim().contains(
-                "does not have a ModuleMainClass attribute")) {
-            throw new AssertionError("Unexpected result[0]: " + result[0]);
+        if (!result[1].trim().equals("args.length: 0")) {
+            throw new AssertionError("Unexpected result[1]: " + result[1]);
         }
     }
 
@@ -77,10 +81,16 @@
         JPackageHelper.createHelloModule();
 
         JPackageHelper.deleteOutputFolder(OUTPUT);
-        validate(JPackageHelper.executeCLI(true, CMD));
+        JPackageHelper.executeCLI(false, CMD1);
 
         JPackageHelper.deleteOutputFolder(OUTPUT);
-        validate(JPackageHelper.executeToolProvider(true, CMD));
+        JPackageHelper.executeToolProvider(false, CMD1);
+
+        JPackageHelper.deleteOutputFolder(OUTPUT);
+        validate(JPackageHelper.executeCLI(true, CMD2));
+
+        JPackageHelper.deleteOutputFolder(OUTPUT);
+        validate(JPackageHelper.executeToolProvider(true, CMD2));
     }
 
 }