--- a/jdk/src/java.base/share/classes/java/net/URLClassLoader.java	Tue Apr 12 21:41:28 2016 +0200
+++ b/jdk/src/java.base/share/classes/java/net/URLClassLoader.java	Tue Apr 12 18:58:21 2016 -0700
@@ -465,23 +465,21 @@
     }
 
     /**
-     * Defines a new package by name in this ClassLoader. The attributes
-     * contained in the specified Manifest will be used to obtain package
-     * version and sealing information. For sealed packages, the additional
-     * URL specifies the code source URL from which the package was loaded.
+     * Defines a new package by name in this {@code URLClassLoader}.
+     * The attributes contained in the specified {@code Manifest}
+     * will be used to obtain package version and sealing information.
+     * For sealed packages, the additional URL specifies the code source URL
+     * from which the package was loaded.
      *
      * @param name  the package name
-     * @param man   the Manifest containing package version and sealing
+     * @param man   the {@code Manifest} containing package version and sealing
      *              information
      * @param url   the code source url for the package, or null if none
-     * @exception   IllegalArgumentException if the package name duplicates
-     *              an existing package either in this class loader or one
-     *              of its ancestors
-     * @return the newly defined Package object
+     * @throws      IllegalArgumentException if the package name is
+     *              already defined by this class loader
+     * @return      the newly defined {@code Package} object
      */
-    protected Package definePackage(String name, Manifest man, URL url)
-        throws IllegalArgumentException
-    {
+    protected Package definePackage(String name, Manifest man, URL url) {
         String path = name.replace('.', '/').concat("/");
         String specTitle = null, specVersion = null, specVendor = null;
         String implTitle = null, implVersion = null, implVendor = null;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/net/URLClassLoader/definePackage/SplitPackage.java	Tue Apr 12 18:58:21 2016 -0700
@@ -0,0 +1,102 @@
+/**
+ * Copyright (c) 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
+ * @bug 8153665
+ * @summary Test two URLClassLoader define Package object of the same name
+ * @library /lib/testlibrary
+ * @build CompilerUtils
+ * @run testng SplitPackage
+ */
+
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.util.jar.Manifest;
+
+import org.testng.annotations.BeforeTest;
+import org.testng.annotations.Test;
+import static org.testng.Assert.*;
+
+public class SplitPackage {
+    private static final Path SRC_DIR = Paths.get(System.getProperty("test.src", "."));
+    private static final Path FOO_DIR = Paths.get("foo");
+    private static final Path BAR_DIR = Paths.get("bar");
+
+    @BeforeTest
+    private void setup() throws Exception {
+        Files.createDirectory(BAR_DIR);
+
+        Path pkgDir = Paths.get("p");
+        // compile classes in package p
+        assertTrue(CompilerUtils.compile(SRC_DIR.resolve(pkgDir), BAR_DIR));
+
+        // move p.Foo to a different directory
+        Path foo = pkgDir.resolve("Foo.class");
+        Files.createDirectories(FOO_DIR.resolve(pkgDir));
+        Files.move(BAR_DIR.resolve(foo), FOO_DIR.resolve(foo),
+                   StandardCopyOption.REPLACE_EXISTING);
+    }
+
+    @Test
+    public void test() throws Exception {
+        URLClassLoader loader1 = new URLClassLoader(new URL[] {
+            FOO_DIR.toUri().toURL()
+        });
+        Loader loader2 = new Loader(new URL[] {
+            BAR_DIR.toUri().toURL()
+        }, loader1);
+
+        Class<?> foo = Class.forName("p.Foo", true, loader2);
+        Class<?> bar = Class.forName("p.Bar", true, loader2);
+        Class<?> baz = Class.forName("p.Baz", true, loader2);
+
+        Package pForFoo = loader1.getDefinedPackage("p");
+        Package pForBar = loader2.getDefinedPackage("p");
+
+        assertEquals(pForFoo.getName(), pForBar.getName());
+        assertTrue(pForFoo != pForBar);
+
+        try {
+            loader2.defineSplitPackage("p");
+        } catch (IllegalArgumentException e) {
+
+        }
+    }
+
+    static class Loader extends URLClassLoader {
+        Loader(URL[] urls, URLClassLoader parent) {
+            super(urls, parent);
+        }
+
+        public Package defineSplitPackage(String name) {
+            Manifest manifest = new Manifest();
+            return super.definePackage(name, manifest, null);
+        }
+    }
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/net/URLClassLoader/definePackage/p/Bar.java	Tue Apr 12 18:58:21 2016 -0700
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 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.
+ */
+
+
+package p;
+
+public class Bar { }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/net/URLClassLoader/definePackage/p/Baz.java	Tue Apr 12 18:58:21 2016 -0700
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 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.
+ */
+
+
+package p;
+
+public class Baz { }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/net/URLClassLoader/definePackage/p/Foo.java	Tue Apr 12 18:58:21 2016 -0700
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 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.
+ */
+
+
+package p;
+
+public class Foo { }