--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/modules/DuplicateClassTest.java	Thu Mar 17 19:04:28 2016 +0000
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @summary Ensure that classes with the same FQNs are OK in unrelated modules.
+ * @library /tools/lib
+ * @modules
+ *      jdk.compiler/com.sun.tools.javac.api
+ *      jdk.compiler/com.sun.tools.javac.main
+ *      jdk.jdeps/com.sun.tools.javap
+ * @build ToolBox ModuleTestBase
+ * @run main DuplicateClassTest
+ */
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class DuplicateClassTest extends ModuleTestBase {
+
+    public static void main(String... args) throws Exception {
+        DuplicateClassTest t = new DuplicateClassTest();
+        t.runTests();
+    }
+
+    @Test
+    void testSimple(Path base) throws Exception {
+        Path m1 = base.resolve("m1");
+        Path m2 = base.resolve("m2");
+        tb.writeJavaFiles(m1,
+                          "module m1 { }",
+                          "package impl; public class Impl { }");
+        tb.writeJavaFiles(m2,
+                          "module m2 { }",
+                          "package impl; public class Impl { }");
+        Path classes = base.resolve("classes");
+        Files.createDirectories(classes);
+
+        String log = tb.new JavacTask()
+                .options("-modulesourcepath", base.toString())
+                .outdir(classes)
+                .files(findJavaFiles(base))
+                .run()
+                .writeAll()
+                .getOutput(ToolBox.OutputKind.DIRECT);
+
+        if (!log.isEmpty())
+            throw new Exception("expected output not found; output: " + log);
+    }
+
+}