FULL PRODUCT VERSION :
java version "1.7.0_95"
OpenJDK Runtime Environment (IcedTea 2.6.4) (7u95-2.6.4-0ubuntu0.14.04.2)
OpenJDK 64-Bit Server VM (build 24.95-b01, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux Wall-E 3.13.0-35-generic #62-Ubuntu SMP Fri Aug 15 01:58:42 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux


EXTRA RELEVANT SYSTEM CONFIGURATION :
unity 7.2.6

A DESCRIPTION OF THE PROBLEM :
If a Frame is set not resizable with the setResizable(false) command, each call to setSize on the frame will move the frame 10 pixels down.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Just execute the test case on Ubuntu with Unity (I don't know about other configurations)

In short, create a JFrame, call setResizable(false), and then every call to setSize will move the frame 28 pixels down.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The frame width is suppose to increase to fit the JTextArea.
ACTUAL -
Each time the frame width increases, the frame is being moved 28 pixels lower for no reason.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
This is the stacktrace of the ComponentMoved method :

at test.Test2$1$3.componentMoved(Test2.java:50)
at java.awt.AWTEventMulticaster.componentMoved(AWTEventMulticaster.java:169)
at java.awt.AWTEventMulticaster.componentMoved(AWTEventMulticaster.java:169)
at java.awt.Component.processComponentEvent(Component.java:6345)
at java.awt.Component.processEvent(Component.java:6296)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Window.processEvent(Window.java:2022)
at java.awt.Component.dispatchEventImpl(Component.java:4872)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Window.dispatchEventImpl(Window.java:2719)
at java.awt.Component.dispatchEvent(Component.java:4698)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:747)
at java.awt.EventQueue.access$300(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:706)
at java.awt.EventQueue$3.run(EventQueue.java:704)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:77)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:720)
at java.awt.EventQueue$4.run(EventQueue.java:718)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:77)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:717)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package test;

import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;

public class Test2 {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                final JFrame mainFrame = new JFrame("test");
                mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                mainFrame.setResizable(false);
                final JTextArea field = new JTextArea() {
                    public Dimension getPreferredSize() {
                        Dimension pref = super.getPreferredSize();
                        return new Dimension(Math.max(30, pref.width),Math.max(20, pref.height));
                    }
                };
                ((AbstractDocument)field.getDocument()).setDocumentFilter(new DocumentFilter() {
                    @Override
                    public void replace(DocumentFilter.FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {
                        super.replace(fb, offset, length, text, attrs);
                        //We make the frame fit the content. We can use pack as well with the same result
                        mainFrame.setSize(mainFrame.getContentPane().getPreferredSize());
                        //mainFrame.pack();(same result with pack)
                        System.out.println(mainFrame.getLocation().y);//The frame is moving down when typing
                    }
                });
                mainFrame.getContentPane().setLayout(new BorderLayout());
                mainFrame.getContentPane().add(field,BorderLayout.CENTER);
                mainFrame.pack();
                mainFrame.setVisible(true);
            }
        });
    }

}
---------- END SOURCE ----------