6992121: StringBuilder.ensureCapacity(int minCap) throws OutOfMemoryError with...

6992121: StringBuilder.ensureCapacity(int minCap) throws OutOfMemoryError with minCap=Integer.MIN_VALUE
Reviewed-by: dholmes, alanb

src/share/classes/java/lang/AbstractStringBuilder.java

@@ -100,7 +100,8 @@ abstract class AbstractStringBuilder implements Appendable, CharSequence {
      * @param   minimumCapacity   the minimum desired capacity.
      */
     public void ensureCapacity(int minimumCapacity) {
-        ensureCapacityInternal(minimumCapacity);
+        if (minimumCapacity > 0)
+            ensureCapacityInternal(minimumCapacity);
     }
 
     /**
@@ -108,6 +109,7 @@ abstract class AbstractStringBuilder implements Appendable, CharSequence {
      * never synchronized.
      */
     private void ensureCapacityInternal(int minimumCapacity) {
+        // overflow-conscious code
         if (minimumCapacity - value.length > 0)
             expandCapacity(minimumCapacity);
     }

src/share/classes/java/util/ArrayList.java

@@ -176,6 +176,11 @@ public class ArrayList<E> extends AbstractList<E>
      * @param minCapacity the desired minimum capacity
      */
     public void ensureCapacity(int minCapacity) {
+        if (minCapacity > 0)
+            ensureCapacityInternal(minCapacity);
+    }
+
+    private void ensureCapacityInternal(int minCapacity) {
         modCount++;
         // overflow-conscious code
         if (minCapacity - elementData.length > 0)
@@ -403,7 +408,7 @@ public class ArrayList<E> extends AbstractList<E>
      * @return <tt>true</tt> (as specified by {@link Collection#add})
      */
     public boolean add(E e) {
-        ensureCapacity(size + 1);  // Increments modCount!!
+        ensureCapacityInternal(size + 1);  // Increments modCount!!
         elementData[size++] = e;
         return true;
     }
@@ -420,7 +425,7 @@ public class ArrayList<E> extends AbstractList<E>
     public void add(int index, E element) {
         rangeCheckForAdd(index);
 
-        ensureCapacity(size + 1);  // Increments modCount!!
+        ensureCapacityInternal(size + 1);  // Increments modCount!!
         System.arraycopy(elementData, index, elementData, index + 1,
                          size - index);
         elementData[index] = element;
@@ -524,7 +529,7 @@ public class ArrayList<E> extends AbstractList<E>
     public boolean addAll(Collection<? extends E> c) {
         Object[] a = c.toArray();
         int numNew = a.length;
-        ensureCapacity(size + numNew);  // Increments modCount
+        ensureCapacityInternal(size + numNew);  // Increments modCount
         System.arraycopy(a, 0, elementData, size, numNew);
         size += numNew;
         return numNew != 0;
@@ -550,7 +555,7 @@ public class ArrayList<E> extends AbstractList<E>
 
         Object[] a = c.toArray();
         int numNew = a.length;
-        ensureCapacity(size + numNew);  // Increments modCount
+        ensureCapacityInternal(size + numNew);  // Increments modCount
 
         int numMoved = size - index;
         if (numMoved > 0)

src/share/classes/java/util/Vector.java

@@ -222,8 +222,10 @@ public class Vector<E>
      * @param minCapacity the desired minimum capacity
      */
     public synchronized void ensureCapacity(int minCapacity) {
-        modCount++;
-        ensureCapacityHelper(minCapacity);
+        if (minCapacity > 0) {
+            modCount++;
+            ensureCapacityHelper(minCapacity);
+        }
     }
 
     /**

test/java/lang/StringBuilder/EnsureCapacity.java

+/*
+ * Copyright (c) 2010, 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 6955504 6992121
+ * @summary Test the StringBuilder.ensureCapacity() with negative minimumCapacity
+ *    and append() method with negative length input argument.
+ *    Also, test the StringBuffer class.
+ */
+
+import java.util.ArrayList;
+import java.util.Vector;
+
+public class EnsureCapacity {
+    public static void main(String[] args) {
+        testStringBuilder();
+        testStringBuffer();
+    }
+
+    private static void checkCapacity(int before, int after) {
+        if (before != after) {
+            throw new RuntimeException("capacity is expected to be unchanged: " +
+                "before=" + before + " after=" + after);
+        }
+    }
+
+    private static void testStringBuilder() {
+        StringBuilder sb = new StringBuilder("abc");
+        int cap = sb.capacity();
+
+        // test if negative minimumCapacity
+        sb.ensureCapacity(Integer.MIN_VALUE);
+        checkCapacity(cap, sb.capacity());
+
+        try {
+            char[] str = {'a', 'b', 'c', 'd'};
+            // test if negative length
+            sb.append(str, 0, Integer.MIN_VALUE + 10);
+            throw new RuntimeException("IndexOutOfBoundsException not thrown");
+        } catch (IndexOutOfBoundsException ex) {
+        }
+    }
+
+    private static void testStringBuffer() {
+        StringBuffer sb = new StringBuffer("abc");
+        int cap = sb.capacity();
+
+        // test if negative minimumCapacity
+        sb.ensureCapacity(Integer.MIN_VALUE);
+        checkCapacity(cap, sb.capacity());
+
+        try {
+            char[] str = {'a', 'b', 'c', 'd'};
+            // test if negative length
+            sb.append(str, 0, Integer.MIN_VALUE + 10);
+            throw new RuntimeException("IndexOutOfBoundsException not thrown");
+        } catch (IndexOutOfBoundsException ex) {
+        }
+    }
+}

test/java/util/ArrayList/EnsureCapacity.java

+/*
+ * Copyright (c) 2010, 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 6992121
+ * @summary Test the ArrayList.ensureCapacity() and Vector.ensureCapacity
+ *    method with negative minimumCapacity input argument.
+ */
+
+import java.util.ArrayList;
+import java.util.Vector;
+
+public class EnsureCapacity {
+    public static void main(String[] args) {
+        testArrayList();
+        testVector();
+    }
+
+    private static void checkCapacity(int before, int after) {
+        if (before != after) {
+            throw new RuntimeException("capacity is expected to be unchanged: " +
+                "before=" + before + " after=" + after);
+        }
+    }
+
+    private static void testArrayList() {
+        ArrayList<String> al = new ArrayList<String>();
+        al.add("abc");
+        al.ensureCapacity(Integer.MIN_VALUE);
+
+        // there is no method to query the capacity of ArrayList
+        // so before and after capacity are not checked
+    }
+
+    private static void testVector() {
+        Vector<String> vector = new Vector<String>();
+        vector.add("abc");
+
+        int cap = vector.capacity();
+        vector.ensureCapacity(Integer.MIN_VALUE);
+        checkCapacity(cap, vector.capacity());
+    }
+}