hello,
JTextPane's contents are stored in its document.(i.e its model).You can retrieve its contents by simplify getting its document..ie

JTextPane text=new JTextPane();
StyledDocument=doc=text.getStyledDocument();

now, 'text' contents are stored in this 'doc'.If u like to set this 'doc' to another JTextPane,u can do the following...
JTextPane text2=new JTextPane();
text.setStyledDocument(doc);

thank yoy