The java.awt.TextComponent class (from which TextArea is derived) has three methods to retrieve mouse selection information. The getSelectedText() method will return a String containing the selected text, and the getSelectionStart() and getSelectionEnd() methods will return the start and end positions of the selected text. If getSelected() returns null, then no text is selected. The TextArea component provides a method called replaceRange() (formerly replaceText() in JDK 1.0.2), with which you can replace the contents of part of the TextArea.