account for Windows behviour changes

test/hotspot/gtest/runtime/test_os.cpp

@@ -430,9 +430,13 @@ TEST_VM(os, realpath) {
   /* test a non-existant path, but provide an adequate buffer */
   errno = 0;
   returnedBuffer = os::realpath(nosuchpath, buffer, sizeof(nosuchpath) + 3);
-  /* Returns ENOENT on Linux, 0 on Windows */
+  /* Returns ENOENT on Linux, 0 on SOME versions of Windows */
 #if defined(_WINDOWS)
-  EXPECT_TRUE(returnedBuffer == buffer);
+  if (returnedBuffer != nullptr) {
+    EXPECT_TRUE(returnedBuffer == buffer);
+  } else {
+    EXPECT_TRUE(errno != 0);
+  }
 #else
   EXPECT_TRUE(returnedBuffer == nullptr);
   EXPECT_TRUE(errno == ENOENT);

test/hotspot/jtreg/serviceability/dcmd/vm/SystemMapZGCTest.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Red Hat, Inc. and/or its affiliates.
+ * 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.testng.annotations.Test;
+import jdk.test.lib.dcmd.CommandExecutor;
+import jdk.test.lib.dcmd.JMXExecutor;
+import jdk.test.lib.process.OutputAnalyzer;
+
+/*
+ * @test
+ * @summary Test of diagnostic command System.map
+ * @library /test/lib
+ * @requires (os.family == "linux" | os.family == "windows")
+ * @modules java.base/jdk.internal.misc
+ *          java.compiler
+ *          java.management
+ *          jdk.internal.jvmstat/sun.jvmstat.monitor
+ * @run testng/othervm -XX:+UseZGC -XX:+UsePerfData SystemMapTest
+ */
+public class SystemMapZGCTest extends SystemMapTestBase {
+    public void run(CommandExecutor executor) {
+        OutputAnalyzer output = executor.execute("System.map");
+        boolean NMTOff = output.contains("NMT is disabled");
+        for (String s: shouldMatchUnconditionally()) {
+            output.shouldMatch(s);
+        }
+        if (!NMTOff) { // expect VM annotations if NMT is on
+            for (String s: shouldMatchIfNMTIsEnabled()) {
+                output.shouldMatch(s);
+            }
+        }
+    }
+
+    @Test
+    public void jmx() {
+        run(new JMXExecutor());
+    }
+}