Try swing test:Swing_JEditorPane/Manual/JTextPaneTest
text is rendered incorrectly(at least, not according to test description)
(7b141)

here is test source code:
/* Bug 4242645*/

import java.awt.*;
import javax.swing.*;
import javax.swing.text.*;
import java.awt.event.*;

public class JTextPaneTest
{
        JTextPane jEditorPane1 = new JTextPane();
    float x = -0.5f;
        JFrame frame;

        public JTextPaneTest()
        {

                frame = new JFrame("TextPane Rendering Test!");
                String info = " \n\n Check while entering text in TextPane \n"+
                              " the line spacing is consitent with Radio button \n"+
                              " selection \n";

                          ButtonGroup group=new ButtonGroup();
                  final JRadioButton rb1=new JRadioButton("0.5");
                  final JRadioButton rb2=new JRadioButton("2");
                  rb1.setSelected(true);
                  group.add(rb1);
                  group.add(rb2);
                  JButton button1 = new JButton("Pass");
                  JButton button2 = new JButton("Fail");
                  button1.setActionCommand("Pass");
                  button2.setActionCommand("Fail");
                      ButtonListener lst = new ButtonListener();
                  button1.addActionListener(lst);
                  button2.addActionListener(lst);
                  JPanel btnpanel = new JPanel();
                  btnpanel.add(button1);
                  btnpanel.add(button2);
                          rb1.addItemListener(new ItemListener() {
                                                          public void itemStateChanged(ItemEvent event) {
                                                                  if(rb1.isSelected()){
                                                                          System.out.println("0.5 size selected");
                                                                          x=-0.5f;
                                                                         try
                                                                                        {
                                                                                                jbInit();
                                                                                        }
                                                                                        catch(Exception e)
                                                                                        {
                                                                                                e.printStackTrace();
                                                                                        }
                                                                                }

                                                        }
                          });

                           rb2.addItemListener(new ItemListener() {
                                                          public void itemStateChanged(ItemEvent event) {
                                                                  if(rb2.isSelected()){
                                                                           System.out.println("2.0 size selected");
                                                                          x=2.0f;
                                                                                 try
                                                                                                {
                                                                                                        jbInit();
                                                                                                }
                                                                                                catch(Exception e)
                                                                                                {
                                                                                                        e.printStackTrace();
                                                                                                }
                                                                                }

                                                        }

                                });

                          btnpanel.add(rb1);
                          btnpanel.add(rb2);
                  JPanel panel = new JPanel(new BorderLayout());

              try
                                        {
                                                jbInit();
                                        }
                                        catch(Exception e)
                                        {
                                                e.printStackTrace();
                                        }

                        panel.add(addInfo(info),BorderLayout.NORTH);
                        panel.add(btnpanel,BorderLayout.SOUTH);
                        panel.add(jEditorPane1, BorderLayout.CENTER);
            frame.getContentPane().add(panel);

                          frame.setSize(new Dimension(400, 300));
                          frame.setTitle("TextPane Rendering Test!");
                          frame.setSize(400,400);
                  frame.setVisible(true);
              frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


        }
        public static void main(String[] args)
        {
                new JTextPaneTest();
        }
        private void jbInit() throws Exception
        {

                System.out.println("Value of x is " +x);
                StyleContext context = StyleContext.getDefaultStyleContext();
                MutableAttributeSet defaultStyle = new SimpleAttributeSet();
                StyleConstants.setFontFamily((MutableAttributeSet)defaultStyle,"Times New Roman");
                StyleConstants.setFontSize((MutableAttributeSet)defaultStyle,12);
                StyleConstants.setLineSpacing((MutableAttributeSet)defaultStyle,x);
                StyleConstants.setSpaceAbove((MutableAttributeSet)defaultStyle,12f);

                DefaultStyledDocument doc = new DefaultStyledDocument(context);
                doc.setParagraphAttributes(0,0,defaultStyle,true);
                jEditorPane1.setDocument(doc);

                        }

public JScrollPane addInfo(String info) {
   JTextArea jta = new JTextArea(info,8,50);
   jta.setEditable(false);
   jta.setLineWrap(true);
   JScrollPane sp = new JScrollPane(jta);
   return sp;

}


        class ButtonListener implements ActionListener {
       public void actionPerformed(ActionEvent ae) {
            JButton button = (JButton)ae.getSource();
            if(button.getActionCommand() == "Pass") {
                System.out.println("User Evaluated Test as Passed");
                System.exit(0);
             } else {
                System.out.println("User Evaluated Test as Failed");
                System.exit(1);
             }

      }
   } // End of ButtonListener class


}
List:
Swing_JEditorPane/Manual/JTextPaneTest