diff -r 000000000000 -r 959103a6100f src/share/classes/com/sun/tools/javac/util/ArrayUtils.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/classes/com/sun/tools/javac/util/ArrayUtils.java	Wed Apr 27 01:34:52 2016 +0800
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 1999, 2013, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 com.sun.tools.javac.util;
+
+import java.lang.reflect.Array;
+
+/** <p><b>This is NOT part of any supported API.
+ *  If you write code that depends on this, you do so at your own risk.
+ *  This code and its internal interfaces are subject to change or
+ *  deletion without notice.</b>
+ */
+public class ArrayUtils {
+
+    private static int calculateNewLength(int currentLength, int maxIndex) {
+        while (currentLength < maxIndex + 1)
+            currentLength = currentLength * 2;
+        return currentLength;
+    }
+
+    public static <T> T[] ensureCapacity(T[] array, int maxIndex) {
+        if (maxIndex < array.length) {
+            return array;
+        } else {
+            int newLength = calculateNewLength(array.length, maxIndex);
+            @SuppressWarnings("unchecked")
+            T[] result = (T[]) Array.newInstance(array.getClass().getComponentType(), newLength);
+            System.arraycopy(array, 0, result, 0, array.length);
+            return result;
+        }
+    }
+
+    public static byte[] ensureCapacity(byte[] array, int maxIndex) {
+        if (maxIndex < array.length) {
+            return array;
+        } else {
+            int newLength = calculateNewLength(array.length, maxIndex);
+            byte[] result = new byte[newLength];
+            System.arraycopy(array, 0, result, 0, array.length);
+            return result;
+        }
+    }
+
+    public static char[] ensureCapacity(char[] array, int maxIndex) {
+        if (maxIndex < array.length) {
+            return array;
+        } else {
+            int newLength = calculateNewLength(array.length, maxIndex);
+            char[] result = new char[newLength];
+            System.arraycopy(array, 0, result, 0, array.length);
+            return result;
+        }
+    }
+
+    public static int[] ensureCapacity(int[] array, int maxIndex) {
+        if (maxIndex < array.length) {
+            return array;
+        } else {
+            int newLength = calculateNewLength(array.length, maxIndex);
+            int[] result = new int[newLength];
+            System.arraycopy(array, 0, result, 0, array.length);
+            return result;
+        }
+    }
+
+}