--- /dev/null	2018-08-14 18:25:04.628316445 -0700
+++ new/test/hotspot/jtreg/runtime/SharedArchiveFile/serviceability/ReplaceCriticalClasses.java	2018-10-21 17:55:07.559317893 -0700
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2016, 2017, 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 Tests how CDS works when critical library classes are replaced with JVMTI ClassFileLoadHook
+ * @library /test/lib
+ * @requires vm.cds
+ *
+ * @comment CDS should not be disabled -- these critical classes will be replaced because JvmtiExport::early_class_hook_env() is true.
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=+early,java/lang/Object,XXX,XXX     -showversion ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=+early,java/lang/String,XXX,XXX     -showversion ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=+early,java/lang/Cloneable,XXX,XXX  -showversion ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=+early,java/io/Serializable,XXX,XXX -showversion ReplaceCriticalClasses
+ *
+ * @comment CDS should not be disabled -- these critical classes cannot be replaced because JvmtiExport::early_class_hook_env() is false.
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=java/lang/Object,XXX,XXX     -showversion ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=java/lang/String,XXX,XXX     -showversion ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=java/lang/Cloneable,XXX,XXX  -showversion ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=java/io/Serializable,XXX,XXX -showversion ReplaceCriticalClasses
+ *
+ * @comment Try to replace classes that are used by the archived subgraph graphs. As of 2018/10/21 the classes won't be replaced because
+ *          all archived subgraphs were loaded in JVMTI_PHASE_PRIMORDIAL.
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=java/util/ArrayList,XXX,XXX             -verbose -showversion -Xlog:cds+heap=debug ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=java/lang/module/ResolvedModule,XXX,XXX -verbose -showversion -Xlog:cds+heap=debug ReplaceCriticalClasses
+ *
+ * @comment Replace classes that are loaded after JVMTI_PHASE_PRIMORDIAL. It's OK to replace such classes even when CDS is enabled.
+ *          Nothing bad should happen.
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=jdk/internal/vm/PostVMInitHook,XXX,XXX  -showversion ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=java/util/Locale,XXX,XXX                -showversion ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=sun/util/locale/BaseLocale,XXX,XXX      -showversion ReplaceCriticalClasses
+ * @run main/othervm/native -Xshare:auto -agentlib:SimpleClassFileLoadHook=java/lang/Readable,XXX,XXX              -showversion ReplaceCriticalClasses
+ */
+
+public class ReplaceCriticalClasses {
+    public static void main(String args[]) {
+        String strings[] = {
+            // interned strings from j.l.Object
+            "@",
+            "nanosecond timeout value out of range",
+            "timeoutMillis value is negative",
+
+            // interned strings from j.l.Integer
+            "0",
+            "0X",
+            "0x",
+            "int"
+        };
+
+        // Make sure the interned string table is same
+        for (String s : strings) {
+            String i = s.intern();
+            if (s != i) {
+                throw new RuntimeException("Interned string mismatch: \"" + s + "\" @ " + System.identityHashCode(s) +
+                                           " vs \"" + i + "\" @ " + System.identityHashCode(i));
+            }
+        }
+        // We have tried to use ClassFileLoadHook to replace critical library classes (which may
+        // may not have succeeded, depending on whether the agent has requested
+        // can_generate_all_class_hook_events/can_generate_early_class_hook_events capabilities).
+        //
+        // In any case, the JVM should have started properly (perhaps with CDS disabled) and
+        // the above operations should succeed.
+        System.out.println("If I can come to here without crashing, things should be OK");
+    }
+}
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