--- old/src/java.base/unix/native/libjava/java_props_md.c	2020-12-10 10:21:23.725554375 +0530
+++ new/src/java.base/unix/native/libjava/java_props_md.c	2020-12-10 10:21:23.409396379 +0530
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2020, 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
@@ -458,7 +458,8 @@
 
         sprops.os_arch = ARCHPROPNAME;
 
-        if (getenv("GNOME_DESKTOP_SESSION_ID") != NULL) {
+        if (getenv("GNOME_DESKTOP_SESSION_ID") != NULL
+            || getenv("XDG_CURRENT_DESKTOP") != NULL) {
             sprops.desktop = "gnome";
         }
         else {
--- /dev/null	2020-12-10 10:01:49.211999948 +0530
+++ new/test/jdk/javax/swing/LookAndFeel/SystemLookAndFeel/SystemLookAndFeelTest.java	2020-12-10 10:21:24.097740369 +0530
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2019, 2020, 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 8226783 8247753
+ * @key headful
+ * @summary Verify System L&F
+ */
+
+/*
+ * Verify the System LAF is what we expect based on platform and,
+ * in at least one case, the desktop environment.
+ * Since changes to the system LAF are a once in a blue moon event,
+ * this test is useful to tell us of unexpected problems.
+ * Note: this test must be run in a headful environment
+ * since otherwise a system LAF may not be available.
+ */
+
+public class SystemLookAndFeelTest {
+
+    public static void main(String[] args) {
+
+        String laf = javax.swing.UIManager.getSystemLookAndFeelClassName();
+        String os = System.getProperty("os.name").toLowerCase();
+        System.out.println("OS is " + os);
+        System.out.println("Reported System LAF is " + laf);
+
+        String expLAF = null;
+        if (os.contains("windows")) {
+            expLAF = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
+        } else if (os.contains("macos")) {
+            expLAF = "com.apple.laf.AquaLookAndFeel";
+        } else if (os.contains("linux") || os.contains("sunos")) {
+            /*
+             * The implementation keys off the following desktop setting to
+             * decide if GTK is an appropriate system L&F.
+             * In its absence, there probably isn't support for the GTK L&F
+             * anyway. It does not tell us if the GTK libraries are available
+             * but they really should be if this is a gnome session.
+             * If it proves necessary the test can perhaps be updated to see
+             * if the GTK LAF is listed as installed and can be instantiated.
+             */
+            String gnome = System.getenv("GNOME_DESKTOP_SESSION_ID");
+            String desktop = System.getenv("XDG_CURRENT_DESKTOP");
+            System.out.println("Gnome desktop session ID is " + gnome);
+            System.out.println("XDG_CURRENT_DESKTOP is set to " + desktop);
+            if (gnome != null ||
+                    (desktop != null && desktop.toLowerCase().contains("gnome"))) {
+                expLAF = "com.sun.java.swing.plaf.gtk.GTKLookAndFeel";
+            } else if (os.contains("linux")) {
+                expLAF = "javax.swing.plaf.metal.MetalLookAndFeel";
+            } else if (os.contains("sunos")) {
+                expLAF = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
+            }
+        }
+        System.out.println("Expected System LAF is " + expLAF);
+        if (expLAF == null) {
+            System.out.println("No match for expected LAF, unknown OS ?");
+            return;
+        }
+        if (!(laf.equals(expLAF))) {
+            throw new RuntimeException("LAF not as expected");
+        }
+    }
+}