6943780: JTabbedPane throws ArrayIndexOutOfBoundsException sometimes

Reviewed-by: alexsch

src/share/classes/javax/swing/plaf/basic/BasicTabbedPaneUI.java

@@ -3350,6 +3350,7 @@ public class BasicTabbedPaneUI extends TabbedPaneUI implements SwingConstants {
         private void updateView() {
             int tabPlacement = tabPane.getTabPlacement();
             int tabCount = tabPane.getTabCount();
+            assureRectsCreated(tabCount);
             Rectangle vpRect = viewport.getBounds();
             Dimension viewSize = viewport.getViewSize();
             Rectangle viewRect = viewport.getViewRect();

test/javax/swing/plaf/basic/BasicTabbedPaneUI/Test6943780.java

+/*
+ * 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 javax.swing.JButton;
+import javax.swing.JTabbedPane;
+import java.awt.Component;
+
+import static javax.swing.SwingUtilities.invokeAndWait;
+
+/*
+ * @test
+ * @bug 4873983 6943780
+ * @summary Tests JTabbedPane with SCROLL_TAB_LAYOUT
+ * @author Sergey Malenkov
+ */
+public class Test6943780 implements Runnable, Thread.UncaughtExceptionHandler {
+    public static void main(String[] args) throws Exception {
+        invokeAndWait(new Test6943780());
+    }
+
+    @Override
+    public void uncaughtException(Thread thread, Throwable throwable) {
+        throwable.printStackTrace();
+        System.exit(1);
+    }
+
+    @Override
+    public void run() {
+        JTabbedPane pane = new JTabbedPane(JTabbedPane.TOP, JTabbedPane.SCROLL_TAB_LAYOUT);
+        pane.addTab("first", new JButton("first"));
+        pane.addTab("second", new JButton("second"));
+        for (Component component : pane.getComponents()) {
+            component.setSize(100, 100);
+        }
+    }
+}