FULL PRODUCT VERSION :
java version "1.7.0_65"
Java(TM) SE Runtime Environment (build 1.7.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Darwin cthulhu.local 13.3.0 Darwin Kernel Version 13.3.0: Tue Jun 3 21:27:35 PDT 2014; root:xnu-2422.110.17~1/RELEASE_X86_64 x86_64

A DESCRIPTION OF THE PROBLEM :
I have a program which creates an HTMLDocument containing a table.

With java version 1.7.0_55, the table renders correctly.
With java version 1.7.0_60 or later - including the current released 1.7.0_65 and 1.8 - the table is duplicated and rendered incorrectly.

REGRESSION. Last worked in version 7u55

ADDITIONAL REGRESSION INFORMATION:
java version "1.7.0_65"
Java(TM) SE Runtime Environment (build 1.7.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
bash-3.2$ setjdk 1.7.0_65
bash-3.2$ java -version
java version "1.7.0_65"
Java(TM) SE Runtime Environment (build 1.7.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)
bash-3.2$ javac Test.java
bash-3.2$ java Test

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A frame will pop up titled "Test HTML Frame"

In 1.7.0_55, there is an HTML table in it with three columns and three rows: one header row and two data rows.
ACTUAL -
A frame will pop up titled "Test HTML Frame"

In 1.7.0_65, the aforementioned table is shown.
It is followed by a duplicate of the same table and an additional table where each cell contains the cell data twice on separate lines.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.io.StringWriter;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.Element;
import javax.swing.text.html.HTMLDocument;
import javax.swing.text.html.HTMLEditorKit;

public abstract class Test
{
public static void generateRow( final StringBuilder buffer, final String tag, final String [] elts )
{
String open = "<" + tag + ">";
String close = "</" + tag + ">";
buffer.append( "<tr>" );
for ( String elt : elts ) {
buffer.append( open );
buffer.append( elt );
buffer.append( close );
}
buffer.append( "</tr>" );
}

public static void generateTable( final StringBuilder buffer )
{
buffer.append( "<table border=1>" );
Test.generateRow( buffer, "th", new String[] { "Column 1", "Column 2", "Column 3" } );
Test.generateRow( buffer, "td", new String[] { "abc", "def", "ghi" } );
Test.generateRow( buffer, "td", new String[] { "123", "456", "789" } );
buffer.append( "</table>" );
}

public static String generateHTML()
{
StringBuilder buffer = new StringBuilder();
Test.generateTable( buffer );
return buffer.toString();
}

private static void printHTML( final HTMLDocument doc )
        {
HTMLEditorKit kit = new HTMLEditorKit();
StringWriter writer = new StringWriter();
try
{
kit.write(writer, doc, 0, doc.getLength());
}
catch ( Exception e )
{
}
String s = writer.toString();
System.out.println( "New HTML = \"" + s + "\"" );
}

private static void createAndShowGUI()
        {
// Create and set up the window.

JFrame frame = new JFrame();
frame.setTitle( "Test HTML Frame" );
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

Container contents = frame.getContentPane();

JEditorPane pane = new JEditorPane();
pane.setContentType( "text/html" );
pane.setEditable( false );

HTMLDocument currentHTML = (HTMLDocument) pane.getDocument();

// Test.printHTML( currentHTML );

Element contentElement = currentHTML.getDefaultRootElement();
while ( !contentElement.isLeaf() ) {
contentElement = contentElement.getElement( contentElement.getElementCount() - 1 );
}

String text = Test.generateHTML();
try
{
currentHTML.insertAfterEnd( contentElement, text );
}
catch ( Exception e )
{
}

// Test.printHTML( currentHTML );

contents.add( pane, BorderLayout.CENTER );

//Display the window.
frame.pack();
frame.setVisible(true);
}

/**
* The main method.
*/

public static final void main( final String[] args )
{
javax.swing.SwingUtilities.invokeLater(
new Runnable() {
public void run() {
createAndShowGUI();
}
} );

while (true ) {
try
{
Thread.sleep( 1000 );
}
catch ( InterruptedException e )
{
break;
}
}
}
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
None found.