Look at the Javadoc for the class JTextPane, JEditorPane, for example, here:

http://download.java.net/jdk6/docs/api/javax/swing/JTextPane.html
http://download.java.net/jdk6/docs/api/javax/swing/JEditorPane.html

Notice the text formatting - after the word "Newlines" the text shifts to the right and remains there until the end of the doc. I suspect that some other classes in javax.swing are affected.