import javax.swing.text.*;

public class Test extends JFrame{

private JTextPane textpane=new JTextPane();

private StyledDocument document=(StyledDocument)textpane.getDocument();

....

public Test(){

......;

setColor();

......;

}

private void setColor(){

SimpleAttributeSet attribute=new SimpleAttributeSet();

StyleConstants.setForeground(attribute,Color.blue);

document.setCharacterAttributes(6,12,attribute,false);

StyleConstants.setForeground(attribute,Color.red);

document.setCharacterAttributes(20,10,attribute,false);

}

......

}