--- /dev/null	2017-11-16 08:17:56.803999947 +0100
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.replacements/src/org/graalvm/compiler/replacements/StringUTF16Substitutions.java	2019-03-12 08:10:52.208069372 +0100
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2018, 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 org.graalvm.compiler.replacements;
+
+import org.graalvm.compiler.api.replacements.ClassSubstitution;
+import org.graalvm.compiler.api.replacements.MethodSubstitution;
+import org.graalvm.compiler.nodes.extended.JavaReadNode;
+import org.graalvm.compiler.nodes.extended.JavaWriteNode;
+import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugin;
+
+// JaCoCo Exclude
+
+/**
+ * Substitutions for {@code StringUTF16} methods for JDK9 and later.
+ */
+@ClassSubstitution(className = "java.lang.StringUTF16", optional = true)
+public class StringUTF16Substitutions {
+
+    @MethodSubstitution
+    public static char getChar(byte[] value, int i) {
+        ReplacementsUtil.runtimeAssert((i << 1) + 1 < value.length, "Trusted caller missed bounds check");
+        return getCharDirect(value, i << 1);
+    }
+
+    /**
+     * Will be intrinsified with an {@link InvocationPlugin} to a {@link JavaReadNode}.
+     */
+    public static native char getCharDirect(byte[] value, int i);
+
+    @MethodSubstitution
+    public static void putChar(byte[] value, int i, int c) {
+        ReplacementsUtil.runtimeAssert((i << 1) + 1 < value.length, "Trusted caller missed bounds check");
+        putCharDirect(value, i << 1, c);
+    }
+
+    /**
+     * Will be intrinsified with an {@link InvocationPlugin} to a {@link JavaWriteNode}.
+     */
+    public static native void putCharDirect(byte[] value, int i, int c);
+}