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/jdk/java/io/Reader/NullReader.java

@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2018, 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.Reader;
+import java.io.IOException;
+import java.io.StringWriter;
+import java.nio.CharBuffer;
+import java.nio.ReadOnlyBufferException;
+
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+/*
+ * @test
+ * @bug 8196298 8204930
+ * @run junit NullReader
+ * @summary Check for expected behavior of Reader.nullReader().
+ */
+public class NullReader {
+    private static Reader openReader;
+    private static Reader closedReader;
+
+    @BeforeAll
+    public static void setup() throws IOException {
+        openReader = Reader.nullReader();
+        closedReader = Reader.nullReader();
+        closedReader.close();
+    }
+
+    @AfterAll
+    public static void closeStream() throws IOException {
+        openReader.close();
+    }
+
+    @Test
+    public void testOpen() {
+        assertNotNull(openReader, "Reader.nullReader() returned null");
+    }
+
+    @Test
+    public void testRead() throws IOException {
+        assertEquals(-1, openReader.read(), "read() != -1");
+    }
+
+    @Test
+    public void testReadBII() throws IOException {
+        assertEquals(-1, openReader.read(new char[1], 0, 1),
+                "read(char[],int,int) != -1");
+    }
+
+    @Test
+    public void testReadBIILenZero() throws IOException {
+        assertEquals(0, openReader.read(new char[1], 0, 0),
+                "read(char[],int,int) != 0");
+    }
+
+    @Test
+    public void testReadCharBuffer() throws IOException {
+        CharBuffer charBuffer = CharBuffer.allocate(1);
+        assertEquals(-1, openReader.read(charBuffer),
+                "read(CharBuffer) != -1");
+    }
+
+    @Test
+    public void testReadCharBufferZeroRemaining() throws IOException {
+        CharBuffer charBuffer = CharBuffer.allocate(0);
+        assertEquals(0, openReader.read(charBuffer),
+                "read(CharBuffer) != 0");
+    }
+
+    @Test
+    public void testReady() throws IOException {
+        assertFalse(openReader.ready());
+    }
+
+    @Test
+    public void testSkip() throws IOException {
+        assertEquals(0, openReader.skip(1), "skip() != 0");
+    }
+
+    @Test
+    public void testTransferTo() throws IOException {
+        assertEquals(0, openReader.transferTo(new StringWriter(7)),
+                "transferTo() != 0");
+    }
+
+    @Test
+    public void testReadClosed() throws IOException {
+        assertThrows(IOException.class, () -> closedReader.read());
+    }
+
+    @Test
+    public void testReadBIIClosed() throws IOException {
+        assertThrows(IOException.class,
+                     () -> closedReader.read(new char[1], 0, 1));
+    }
+
+    @Test
+    public void testReadCharBufferClosed() throws IOException {
+        CharBuffer charBuffer = CharBuffer.allocate(0);
+        assertThrows(IOException.class, () -> closedReader.read(charBuffer));
+    }
+
+    @Test
+    public void testReadCharBufferZeroRemainingClosed() throws IOException {
+        CharBuffer charBuffer = CharBuffer.allocate(0);
+        assertThrows(IOException.class, () -> closedReader.read(charBuffer));
+    }
+
+    @Test
+    public void testReadyClosed() throws IOException {
+        assertThrows(IOException.class, () -> closedReader.ready());
+    }
+
+    @Test
+    public void testSkipClosed() throws IOException {
+        assertThrows(IOException.class, () -> closedReader.skip(1));
+    }
+
+    @Test
+    public void testTransferToClosed() throws IOException {
+        assertThrows(IOException.class,
+                     () -> closedReader.transferTo(new StringWriter(7)));
+    }
+}