How to change highlighting color in Java Swing TextArea? And also, change the beginning of text corresponding to the highlighting location

Problem 1: BY using defaulthighlighter, I can make the focused lines change to blue. Now I want to change it to other colors. Do anyone know how to change this parameter? --- solved

Problem 2: pos is the beginning index of my substring which I want to highlight. I use setCaretPosition(pos); to update the showing content. But it always appears at the bottom of the window. I want to have it at the top. Could anyone tell me how to deal with that?

I use one demo to show my problem:

import java.awt.Color;
import java.net.MalformedURLException;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultHighlighter;

public class Test {
    public static void main(final String[] args) throws MalformedURLException {
        SwingUtilities.invokeLater(new Runnable() {

        @Override
        public void run() {
            try {
                init();
            } catch (BadLocationException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    });
}

private static void init() throws BadLocationException {
    JFrame frame = new JFrame();
    final JTextArea textArea = new JTextArea();
    JScrollPane pane = new JScrollPane(textArea);
    textArea.setText("Something. Something else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nSomething. Samething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nSomething. Sbmething else.\nA second line\na third line"
            + "Blabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\nBlabla\n"
            + "Blabla\nBlabla\nB