8381567: ProcessHandle.descendants fails with ArrayIndexOutOfBoundException for process 0

src/java.base/macosx/native/libjava/ProcessHandleImpl_macosx.c

@@ -203,6 +203,11 @@ pid_t os_getParentPidAndTimings(JNIEnv *env, pid_t jpid,
     struct kinfo_proc kp;
     size_t bufSize = sizeof kp;
 
+    if (jpid == 0) {
+        // macos would return a process 0.  It's not a real process
+        return -1;
+    }
+
     // Read the process info for the specific pid
     int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, pid};
 

test/jdk/java/lang/ProcessHandle/PidZero.java

@@ -0,0 +1,45 @@
+/*
+ * 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 org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/*
+ * @test
+ * @bug 8381567
+ * @summary ProcessHandle.descendants fails with AIOOE for process 0
+ * @requires os.family == "mac"
+ * @run junit PidZero
+ */
+public class PidZero {
+    /**
+     * Test of ProcessHandle.descendants for pid 0
+     * Only Macos allows a ProcessHandle to be instantiated for pid 0
+     * which includes all processes on the system, but the implementation
+     * throws ArrayIndexOutOfBoundException without this fix.
+     */
+    @Test
+    public void test() {
+         assertTrue(ProcessHandle.of(0).isEmpty());
+    }
+}