I've been happy with the Sun JRE version.
The following command will tell you for sure what JRE you are using.
You may have multiple JRE's on your machine, if this is the case then synaptic package manager may tell you that you have the Sun JRE installed but you will not actually be using it when you invoke the "java" command. The above java version command will tell you what JRE you are using.
Also, there are three things you can do to get Java GUI's looking better without too much work.
1. Using the "native look and feel".
2. Create your own base JPanel class and enable antialiasing.
Code:
public class JBasePanel extends JPanel {
@Override
public void paint(Graphics g){
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
}
}
All panels you create should extend this.
3. Manually set your fonts to something sensible like arial.
There are a lot of other things you can do, the above tips are just the easy ones.