Surprisingly, you cannot turn off file renaming / creating new directories from JFileChooser itself. As you correctly understood, you need to disconnect this "FileChooser" function from UIManager.
, :
http://www.coderanch.com/t/555535/GUI/java/FileChooser-readOnly
Boolean old = UIManager.getBoolean("FileChooser.readOnly");
UIManager.put("FileChooser.readOnly", Boolean.TRUE);
JFileChooser fc = new JFileChooser(".");
UIManager.put("FileChooser.readOnly", old);
, "FileChooser.readOnly" .