--- a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/Extern.java	Sat Jul 13 12:15:17 2019 -0400
+++ b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/Extern.java	Mon Jul 22 16:10:25 2019 -0700
@@ -409,9 +409,10 @@
                         }
                         checkLinkCompatibility(elemname, moduleName, path);
                         Item item = new Item(elemname, elempath, relative);
-                        packageItems.computeIfAbsent(moduleName == null ?
-                            DocletConstants.DEFAULT_ELEMENT_NAME : moduleName, k -> new TreeMap<>())
-                            .put(elemname, item);
+                        packageItems.computeIfAbsent(
+                                moduleName == null ? DocletConstants.DEFAULT_ELEMENT_NAME : moduleName,
+                                k -> new TreeMap<>())
+                            .putIfAbsent(elemname, item); // first-one-wins semantics
                     }
                 }
             }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/jdk/javadoc/doclet/testLinkOption/TestOptionOrder.java	Mon Jul 22 16:10:25 2019 -0700
@@ -0,0 +1,150 @@
+/*
+ * Copyright (c) 2018, 2019, 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 8222791
+ * @summary Order of evaluation of -link params in Javadoc tool reversed:
+ *          regression with split packages
+ * @library /tools/lib ../../lib
+ * @modules
+ *      jdk.javadoc/jdk.javadoc.internal.api
+ *      jdk.javadoc/jdk.javadoc.internal.tool
+ *      jdk.compiler/com.sun.tools.javac.api
+ *      jdk.compiler/com.sun.tools.javac.main
+ * @build toolbox.JavacTask toolbox.JavadocTask toolbox.ToolBox
+ * @build javadoc.tester.*
+ * @run main TestOptionOrder
+ */
+
+import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import toolbox.JavacTask;
+import toolbox.JavadocTask;
+import toolbox.Task;
+import toolbox.ToolBox;
+
+import javadoc.tester.JavadocTester;
+
+public class TestOptionOrder extends JavadocTester {
+    final ToolBox tb;
+
+    public static void main(String... args) throws Exception {
+        TestOptionOrder tester = new TestOptionOrder();
+        tester.runTests(m -> new Object[] { Path.of(m.getName())} );
+    }
+
+    TestOptionOrder() throws Exception {
+        tb = new ToolBox();
+    }
+
+    enum Kind { PACKAGE_LIST, ELEMENT_LIST };
+
+    @Test
+    public void testLib1Lib2PackageList(Path base) throws Exception {
+        test(base, "lib1", "lib2", Kind.PACKAGE_LIST);
+    }
+
+    @Test
+    public void testLib1Lib2ElementList(Path base) throws Exception {
+        test(base, "lib1", "lib2", Kind.ELEMENT_LIST);
+    }
+
+    @Test
+    public void testLib2Lib1PackageList(Path base) throws Exception {
+        test(base, "lib2", "lib1", Kind.PACKAGE_LIST);
+    }
+
+    @Test
+    public void testLib2Lib1ElementList(Path base) throws Exception {
+        test(base, "lib2", "lib1", Kind.ELEMENT_LIST);
+    }
+
+    private void test(Path base, String first, String second, Kind kind) throws Exception {
+        createLib(base, first, kind);
+        createLib(base, second, kind);
+
+        Path src = base.resolve("src");
+
+        tb.writeJavaFiles(src,
+            "package app;\n"
+            + "/** Lorem ipsum.\n"
+            + " *  @see lib.LibClass\n"
+            + " */\n"
+            + "public class App {\n"
+            + "    /** Reference to LibClass. */\n"
+            + "    public lib.LibClass lc;\n"
+            + "}\n");
+
+        javadoc("-d", base.resolve("out").toString(),
+                "-classpath",
+                    base.resolve(first).resolve("classes")
+                    + File.pathSeparator
+                    + base.resolve(second).resolve("classes"),
+                "-linkoffline",
+                    "http://example.com/" + first,
+                    base.resolve(first).resolve("api").toString(),
+                "-linkoffline",
+                    "http://example.com/" + second,
+                    base.resolve(second).resolve("api").toString(),
+                "-sourcepath", src.toString(),
+                "app");
+
+         checkOrder("app/App.html",
+                // Instance in See Also
+                "<dd><a href=\"http://example.com/" + first + "/lib/LibClass.html",
+                // Instance in Field declaration
+                "<td class=\"colFirst\"><code><a href=\"http://example.com/" + first + "/lib/LibClass.html"
+                );
+    }
+
+    private void createLib(Path base, String name, Kind kind) throws Exception {
+        Path libBase = Files.createDirectories(base.resolve(name));
+        Path libSrc = libBase.resolve("src");
+
+        tb.writeJavaFiles(libSrc,
+            "package lib;\n"
+            + "/** Library " + name + ".*/\n"
+            + "public class LibClass { }\n");
+
+        new JavacTask(tb)
+            .outdir(Files.createDirectories(libBase.resolve("classes")))
+            .files(tb.findJavaFiles(libSrc))
+            .run(Task.Expect.SUCCESS);
+
+        Path libApi = libBase.resolve("api");
+        new JavadocTask(tb)
+            .sourcepath(libSrc)
+            .outdir(Files.createDirectories(libBase.resolve("api")))
+            .options("lib")
+            .run(Task.Expect.SUCCESS);
+
+        if (kind == Kind.PACKAGE_LIST) {
+            Path elementList = libApi.resolve("element-list");
+            Path packageList = libApi.resolve("package-list");
+            Files.move(elementList, packageList);
+        }
+    }
+}