undefect. CWE-407 — 63 sites patched across 27 ecosystems

Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com Patches, unit tests, benchmarks, whitepaper, and outreach briefs. Public domain — no copyright claimed. Use freely.
2026-03-26 17:11:57 -04:00 · 2026-03-26 17:11:57 -04:00 · 0a580b313d
commit 0a580b313d
70422 changed files with 17213626 additions and 0 deletions
--- a/test/jdk/java/util/Locale/HashCodeTest.java
+++ b/test/jdk/java/util/Locale/HashCodeTest.java
@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2007, 2023, 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 4944561
+ * @summary Test hashCode() to have less than 10% of hash code conflicts.
+ * @modules jdk.localedata
+ * @run junit HashCodeTest
+ */
+
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+public class HashCodeTest {
+
+    // Ensure Locale.hashCode() has less than 10% conflicts
+    @Test
+    public void hashConflictsTest() {
+        Locale[] locales = Locale.getAvailableLocales();
+        int min = Integer.MAX_VALUE;
+        int max = Integer.MIN_VALUE;
+        Map<Integer, Locale> map = new HashMap<>(locales.length);
+        int conflicts = 0;
+
+        for (Locale loc : locales) {
+            int hc = loc.hashCode();
+            min = Math.min(hc, min);
+            max = Math.max(hc, max);
+            Integer key = hc;
+            if (map.containsKey(key)) {
+                conflicts++;
+                System.out.println("conflict: " + map.get(key) + ", " + loc);
+            } else {
+                map.put(key, loc);
+            }
+        }
+        System.out.println(locales.length + " locales: conflicts=" + conflicts
+                + ", min=" + min + ", max=" + max + ", diff=" + (max - min));
+        assertFalse(conflicts >= (locales.length / 10),
+                String.format("%s conflicts per %s locales", conflicts, locales.length));
+    }
+}