The java.awt.TextArea internally handles scrolling. JTextArea is different in that it doesn't manage scrolling, but implements the swing Scrollable interface. This allows it to be placed inside a JScrollPane if scrolling behavior is desired, and used directly if scrolling is not desired.
JTextArea area = new JTextArea("Hier text);
JScrollPane scroll = new JScrollPane(area);
scroll.setPreferredSize(new DImension(200,50));