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.

test/langtools/jdk/jshell/ConcurrentHistoryLoadingTest.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2026, 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.
+ */
+
+import java.io.ByteArrayInputStream;
+import java.util.Arrays;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.prefs.Preferences;
+
+import jdk.jshell.tool.JavaShellToolBuilder;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+/*
+ * @test
+ * @bug 8347418
+ * @summary Verify that loading of JShell history doesn't lead to a
+ *          NullPointerException when the Preferences are modified concurrently.
+ * @run junit ConcurrentHistoryLoadingTest
+ */
+public class ConcurrentHistoryLoadingTest {
+
+    private static final String HISTORY_LINE_PREFIX = "HISTORY_LINE_";
+
+    @Test
+    public void testConcurrentHistoryLoading() throws Throwable {
+        AtomicBoolean removeOnAccess = new AtomicBoolean();
+        Preferences testPrefs = new ReplToolTesting.MemoryPreferences() {
+            @Override
+            protected String getSpi(String key) {
+                String result = super.getSpi(key);
+                if (key.startsWith(HISTORY_LINE_PREFIX) && removeOnAccess.getAndSet(false)) {
+                    for (String key2Remote : keysSpi()) {
+                        remove(key2Remote);
+                    }
+                }
+                return result;
+            }
+        };
+        StringBuilder input = new StringBuilder();
+        int max = 10;
+        for (int j = 0; j < max; j++) {
+            input.append("int x").append(j).append(" = 42\n");
+        }
+        JavaShellToolBuilder
+                .builder()
+                .persistence(testPrefs)
+                .in(new ByteArrayInputStream(input.toString().getBytes()), null)
+                .start();
+        Assertions.assertEquals(10, Arrays.stream(testPrefs.keys())
+                .filter(key -> key.startsWith(HISTORY_LINE_PREFIX))
+                .count());
+        removeOnAccess.set(true);
+        JavaShellToolBuilder
+                .builder()
+                .persistence(testPrefs)
+                .in(new ByteArrayInputStream(input.toString().getBytes()), null)
+                .start();
+
+    }
+}