--- a/src/share/classes/sun/awt/AppContext.java	Wed Jan 15 20:25:48 2014 +0100
+++ b/src/share/classes/sun/awt/AppContext.java	Wed Jan 15 20:29:07 2014 +0100
@@ -838,6 +838,15 @@
                 return (numAppContexts.get() == 1 && mainAppContext != null);
             }
 
+            private boolean hasRootThreadGroup(final AppContext ecx) {
+                return AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
+                    @Override
+                    public Boolean run() {
+                        return ecx.threadGroup.getParent() == null;
+                    }
+                });
+            }
+
             /**
              * Returns the AppContext used for applet logging isolation, or null if
              * the default global context can be used.
@@ -885,7 +894,7 @@
                 // See: JDK-8023258
                 final boolean isMainAppContext = ecx == null
                     || mainAppContext == ecx
-                    || mainAppContext == null && ecx.threadGroup.getParent() == null;
+                    || mainAppContext == null && hasRootThreadGroup(ecx);
 
                 return isMainAppContext ? null : ecx;
             }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/java/util/logging/TestMainAppContext.java	Wed Jan 15 20:29:07 2014 +0100
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2013, 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.util.logging.Logger;
+import sun.awt.AppContext;
+import sun.awt.SunToolkit;
+
+
+/**
+ * @test
+ * @bug 8026404
+ * @summary checks that calling getLogger() from a Thread whose ThreadGroup is
+ *          a child of the main root group doesn't throw an exception.
+ * @build TestMainAppContext
+ * @run main/othervm TestMainAppContext
+ * @author danielfuchs
+ */
+public class TestMainAppContext {
+
+    static volatile Throwable thrown = null;
+
+    public static void main(String... args) throws Exception {
+        ThreadGroup rootTG = Thread.currentThread().getThreadGroup();
+        while (rootTG.getParent() != null) {
+            rootTG = rootTG.getParent();
+        }
+
+        ThreadGroup tg = new ThreadGroup(rootTG, "FakeApplet");
+        final Thread t1 = new Thread(tg, "createNewAppContext") {
+            @Override
+            public void run() {
+                try {
+                    AppContext context = SunToolkit.createNewAppContext();
+                } catch(Throwable t) {
+                    thrown = t;
+                }
+            }
+        };
+        t1.start();
+        t1.join();
+        if (thrown != null) {
+            throw new RuntimeException("Unexpected exception: " + thrown, thrown);
+        }
+        Thread t2 = new Thread(tg, "BugDetector") {
+
+            @Override
+            public void run() {
+                try {
+                    Logger.getLogger("foo").info("Done");
+                } catch (Throwable x) {
+                    thrown = x;
+                }
+            }
+
+        };
+
+        System.setSecurityManager(new SecurityManager());
+        t2.start();
+        t2.join();
+        if (thrown != null) {
+            throw new RuntimeException("Test failed: " + thrown, thrown);
+        }
+
+    }
+
+}