# HG changeset patch
# User igerasim
# Date 1456167313 -10800
#      Mon Feb 22 21:55:13 2016 +0300
# Node ID 94b1fcb32e96d932558dfefcf27d72a63c0eb7f1
# Parent  b9b28d7137cd2080c5ee97323315ca4aa0405486
[mq]: 8149330-Friendly-realloc-in-StringBuilder

diff --git a/src/java.base/share/classes/java/lang/AbstractStringBuilder.java b/src/java.base/share/classes/java/lang/AbstractStringBuilder.java
--- a/src/java.base/share/classes/java/lang/AbstractStringBuilder.java
+++ b/src/java.base/share/classes/java/lang/AbstractStringBuilder.java
@@ -145,6 +145,14 @@
     }
 
     /**
+     * The maximum size of array to allocate (unless necessary).
+     * Some VMs reserve some header words in an array.
+     * Attempts to allocate larger arrays may result in
+     * OutOfMemoryError: Requested array size exceeds VM limit
+     */
+    private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
+
+    /**
      * This implements the expansion semantics of ensureCapacity with no
      * size check or synchronization.
      */
@@ -153,17 +161,15 @@
         if (newCapacity - minimumCapacity < 0) {
             newCapacity = minimumCapacity;
         }
-        if (newCapacity < 0) {
-            if (minimumCapacity < 0) {// overflow
+
+        final int SAFE_BOUND = (MAX_ARRAY_SIZE >> coder);
+        if (((SAFE_BOUND - newCapacity) | newCapacity) < 0) {
+            final int UNSAFE_BOUND = (Integer.MAX_VALUE >> coder);
+            if (UNSAFE_BOUND - minimumCapacity < 0) { // overflow
                 throw new OutOfMemoryError();
             }
-            newCapacity = Integer.MAX_VALUE;
-        }
-        if (coder != LATIN1 && newCapacity > StringUTF16.MAX_LENGTH) {
-            if (minimumCapacity >= StringUTF16.MAX_LENGTH) {
-                throw new OutOfMemoryError();
-            }
-            newCapacity = StringUTF16.MAX_LENGTH;
+            newCapacity = (minimumCapacity > SAFE_BOUND)
+                    ? minimumCapacity : SAFE_BOUND;
         }
         this.value = Arrays.copyOf(value, newCapacity << coder);
     }
diff --git a/test/java/lang/StringBuilder/HugeCapacity.java b/test/java/lang/StringBuilder/HugeCapacity.java
new file mode 100644
--- /dev/null
+++ b/test/java/lang/StringBuilder/HugeCapacity.java
@@ -0,0 +1,66 @@
+/*
+ * 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 8149330
+ * @summary Capacity should not get close to Integer.MAX_VALUE unless
+ *          necessary
+ * @run main/othervm -Xmx5G HugeCapacity
+ * @ignore This test has huge memory requirements
+ */
+
+public class HugeCapacity {
+    private static int failures = 0;
+
+    public static void main(String[] args) {
+        testLatin1();
+        testUtf8();
+        if (failures > 0) {
+            throw new RuntimeException(failures + " tests failed");
+        }
+    }
+
+    private static void testLatin1() {
+        try {
+            StringBuilder sb = new StringBuilder();
+            sb.ensureCapacity(Integer.MAX_VALUE / 2);
+            sb.ensureCapacity(Integer.MAX_VALUE / 2 + 1);
+        } catch (OutOfMemoryError oom) {
+            oom.printStackTrace();
+            failures++;
+        }
+    }
+
+    private static void testUtf8() {
+        try {
+            StringBuilder sb = new StringBuilder();
+            sb.append('\u042b');
+            sb.ensureCapacity(Integer.MAX_VALUE / 4);
+            sb.ensureCapacity(Integer.MAX_VALUE / 4 + 1);
+        } catch (OutOfMemoryError oom) {
+            oom.printStackTrace();
+            failures++;
+        }
+    }
+}