--- old/src/java.desktop/share/classes/javax/swing/plaf/basic/BasicRadioButtonUI.java	Wed Apr 29 15:01:44 2015
+++ new/src/java.desktop/share/classes/javax/swing/plaf/basic/BasicRadioButtonUI.java	Wed Apr 29 15:01:43 2015
@@ -438,7 +438,7 @@
         // to the button group or not
         Component getFocusTransferBaseComponent(boolean next){
             Component focusBaseComp = activeBtn;
-            Window container = SwingUtilities.getWindowAncestor(activeBtn);
+            Container container = focusBaseComp.getFocusCycleRootAncestor();
             if (container != null) {
                 FocusTraversalPolicy policy = container.getFocusTraversalPolicy();
                 Component comp = next ? policy.getComponentAfter(container, activeBtn)
--- /dev/null	Wed Apr 29 15:01:51 2015
+++ new/test/javax/swing/JRadioButton/8075609/bug8075609.java	Wed Apr 29 15:01:48 2015
@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2015, 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
+ * @library ../../regtesthelpers
+ * @build Util
+ * @bug 8075609
+ * @summary  IllegalArgumentException when transferring focus from JRadioButton using tab
+ * @author Vivi An
+ * @run main bug8075609
+ */
+
+import javax.swing.*;
+import javax.swing.event.*;
+import java.awt.event.*;
+import java.awt.*;
+import sun.awt.SunToolkit;
+
+public class bug8075609 {
+    private static Robot robot;
+    private static SunToolkit toolkit;
+    private static JTextField textField;
+    
+    public static void main(String args[]) throws Throwable {
+        SwingUtilities.invokeAndWait(new Runnable() {
+            public void run() {
+                createAndShowGUI();
+            }
+        });
+
+        robot = new Robot();
+        Thread.sleep(100);
+
+        robot.setAutoDelay(100);
+        toolkit = (SunToolkit) Toolkit.getDefaultToolkit();
+
+        // Radio button group tab key test 
+        runTest1();
+    }
+
+    private static void createAndShowGUI() {
+        JFrame mainFrame = new JFrame("Bug 8075609 - 1 test");
+        
+        JPanel rootPanel = new JPanel();
+        rootPanel.setLayout(new BorderLayout());
+        
+        JPanel formPanel = new JPanel();
+        formPanel.setFocusTraversalPolicy(new LayoutFocusTraversalPolicy());
+        formPanel.setFocusCycleRoot(true);
+        
+        JRadioButton option1 = new JRadioButton("Option 1", true);
+        JRadioButton option2 = new JRadioButton("Option 2");
+        
+        ButtonGroup radioButtonGroup = new ButtonGroup();
+        radioButtonGroup.add(option1);
+        radioButtonGroup.add(option2);
+        
+        formPanel.add(option1);
+        formPanel.add(option2);
+        textField = new JTextField("Another focusable component");
+        formPanel.add(textField);
+        
+        rootPanel.add(formPanel, BorderLayout.CENTER);
+        
+        JButton okButton = new JButton("OK");
+        rootPanel.add(okButton, BorderLayout.SOUTH);
+        
+        mainFrame.add(rootPanel);
+        mainFrame.pack();
+        mainFrame.setVisible(true);
+        mainFrame.toFront();
+    }
+
+    // Radio button Group as a single component when traversing through tab key
+    private static void runTest1() throws Exception{
+        hitKey(robot, KeyEvent.VK_TAB);
+
+        robot.setAutoDelay(1000 );
+        SwingUtilities.invokeAndWait(new Runnable() {
+            public void run() {
+                if (textField.hasFocus()) {
+                    System.out.println("Radio Button Group Go To Next Component through Tab Key failed");
+                    throw new RuntimeException("Focus is not on textField as Expected");
+                }
+            }
+        });
+    }
+    
+    private static void hitKey(Robot robot, int keycode) {
+        robot.keyPress(keycode);
+        robot.keyRelease(keycode);
+        toolkit.realSync();
+    }
+}