--- a/src/share/classes/javax/swing/JViewport.java	Wed Feb 29 16:19:10 2012 +0400
+++ b/src/share/classes/javax/swing/JViewport.java	Mon Mar 05 15:27:15 2012 +0200
@@ -27,9 +27,7 @@
 
 import java.awt.*;
 import java.awt.event.*;
-import java.awt.image.VolatileImage;
 import java.awt.peer.ComponentPeer;
-import java.applet.Applet;
 import java.beans.Transient;
 import javax.swing.plaf.ViewportUI;
 
@@ -265,6 +263,14 @@
      */
     private boolean hasHadValidView;
 
+    /**
+     * When view is changed we have to synchronize scrollbar values
+     * with viewport (see the BasicScrollPaneUI#syncScrollPaneWithViewport method).
+     * This flag allows to invoke that method while ScrollPaneLayout#layoutContainer
+     * is running.
+     */
+    private boolean viewChanged;
+
     /** Creates a <code>JViewport</code>. */
     public JViewport() {
         super();
@@ -830,7 +836,9 @@
             backingStoreImage = null;
         }
         super.reshape(x, y, w, h);
-        if (sizeChanged) {
+        if (sizeChanged || viewChanged) {
+            viewChanged = false;
+
             fireStateChanged();
         }
     }
@@ -967,6 +975,8 @@
             hasHadValidView = true;
         }
 
+        viewChanged = true;
+
         revalidate();
         repaint();
     }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/javax/swing/JViewport/7107099/bug7107099.java	Mon Mar 05 15:27:15 2012 +0200
@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2012, 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 7107099
+   @summary JScrollBar does not show up even if there are enough lebgth of textstring in textField
+   @author Pavel Porvatov
+*/
+
+import sun.awt.SunToolkit;
+
+import javax.swing.*;
+import java.awt.*;
+
+public class bug7107099 {
+    private static JFrame frame;
+    private static JTextArea textarea;
+    private static JScrollPane scrollPane;
+
+    private static int value;
+    private static int min;
+    private static int max;
+    private static int extent;
+
+    public static void main(String[] args) throws Exception {
+        SunToolkit toolkit = (SunToolkit) Toolkit.getDefaultToolkit();
+
+        SwingUtilities.invokeAndWait(new Runnable() {
+            @Override
+            public void run() {
+                textarea = new JTextArea("before###1###\nbefore###2###\nbefore###3###\nbefore###4###\nbefore###5###\n");
+
+                scrollPane = new JScrollPane(textarea);
+                scrollPane.setPreferredSize(new Dimension(100, 50));
+
+                frame = new JFrame();
+                frame.setLayout(new BorderLayout());
+                frame.setSize(200, 200);
+                frame.add(scrollPane, BorderLayout.SOUTH);
+                frame.setVisible(true);
+            }
+        });
+
+        toolkit.realSync();
+
+        SwingUtilities.invokeAndWait(new Runnable() {
+            @Override
+            public void run() {
+                BoundedRangeModel model = scrollPane.getVerticalScrollBar().getModel();
+
+                value = model.getValue();
+                min = model.getMinimum();
+                max = model.getMaximum();
+                extent = model.getExtent();
+
+                // Do tricky manipulation for testing purpose
+                textarea.setText(null);
+                scrollPane.setViewportView(textarea);
+                textarea.setText("after###1###\nafter###1###\nafter###1###\nafter###1###\nafter###1###\n");
+                textarea.setCaretPosition(0);
+            }
+        });
+
+        toolkit.realSync();
+
+        SwingUtilities.invokeAndWait(new Runnable() {
+            @Override
+            public void run() {
+                BoundedRangeModel model = scrollPane.getVerticalScrollBar().getModel();
+
+                if (value != model.getValue() ||
+                        min != model.getMinimum() ||
+                        max != model.getMaximum() ||
+                        extent != model.getExtent()) {
+                    throw new RuntimeException("Test bug7107099 failed");
+                }
+
+                System.out.println("Test bug7107099 passed");
+
+                frame.dispose();
+            }
+        });
+    }
+}