How to prevent JScrollPane arrow key handling from moving caret when Scroll Pane wraps Text Pane

Question

I have the following requirements:

I need a scrollable JTextPane. The user may type into this text pane, or text may be inserted into it that is not typed by the us

Answer 1

You're going to have to modify the KeyBindings

Try this to start with

InputMap im = textArea.getInputMap(WHEN_FOCUSED);
ActionMap am = textArea.getActionMap();

am.get("caret-down").setEnabled(false);
am.get("caret-up").setEnabled(false);

Now that you have that working, you need to worry about all these

selection-up = shift pressed UP
caret-next-word = ctrl pressed RIGHT
selection-previous-word = shift ctrl pressed LEFT
selection-up = shift pressed KP_UP
caret-down = pressed DOWN
caret-previous-word = ctrl pressed LEFT
caret-end-line = pressed END
selection-page-up = shift pressed PAGE_UP
caret-up = pressed KP_UP
delete-next = pressed DELETE
caret-begin = ctrl pressed HOME
selection-backward = shift pressed LEFT
caret-end = ctrl pressed END
delete-previous = pressed BACK_SPACE
selection-next-word = shift ctrl pressed RIGHT
caret-backward = pressed LEFT
caret-backward = pressed KP_LEFT
selection-forward = shift pressed KP_RIGHT
delete-previous = ctrl pressed H
unselect = ctrl pressed BACK_SLASH
insert-break = pressed ENTER
selection-begin-line = shift pressed HOME
caret-forward = pressed RIGHT
selection-page-left = shift ctrl pressed PAGE_UP
selection-down = shift pressed DOWN
page-down = pressed PAGE_DOWN
delete-previous-word = ctrl pressed BACK_SPACE
delete-next-word = ctrl pressed DELETE
selection-backward = shift pressed KP_LEFT
selection-page-right = shift ctrl pressed PAGE_DOWN
caret-next-word = ctrl pressed KP_RIGHT
selection-end-line = shift pressed END
caret-previous-word = ctrl pressed KP_LEFT
caret-begin-line = pressed HOME
caret-down = pressed KP_DOWN
selection-forward = shift pressed RIGHT
selection-end = shift ctrl pressed END
selection-previous-word = shift ctrl pressed KP_LEFT
selection-down = shift pressed KP_DOWN
insert-tab = pressed TAB
caret-up = pressed UP
selection-begin = shift ctrl pressed HOME
selection-page-down = shift pressed PAGE_DOWN
delete-previous = shift pressed BACK_SPACE
caret-forward = pressed KP_RIGHT
selection-next-word = shift ctrl pressed KP_RIGHT
page-up = pressed PAGE_UP

Answer 2

What if you let user place caret e.g. to let him select and copy some text?

I would add a DocumentFilter (or override insertString() method of the Document) and in all cases perform insert in the doc.getLength() position and resetting the caret to the doc.getLength() position after the insert.