I find it is always best to do any special alignment by placing your components in a JPanel
and then smartly choosing the correct layout manager for the panel.
JEditorPane editor = new JEditorPane();
editor.setBorder(BorderFactory.createLineBorder(Color.RED, 1));
editor.setText("..large text block..");
JScrollPane scrollPane = new JScrollPane(editor);
JPanel panel = new JPanel();
BoxLayout layout = new BoxLayout(panel, BoxLayout.Y_AXIS);
panel.setLayout(layout);
panel.add(Box.createVerticalGlue());
panel.add(scrollPane);
panel.add(Box.createVerticalGlue());
JFrame frame = new JFrame();
frame.setSize(600, 400);
frame.add(panel);
frame.setVisible(true);
This really just centers the editor vertically, not the text within the editor which I think is what you are trying for. For more on BoxLayout
see http://docs.oracle.com/javase/tutorial/uiswing/layout/box.html
JEditorPane
? or you want to place the widget in the center only? – Cartercarteret