When I was trying to start tightvncviewer in Ubuntu, I got this exception:
Exception in thread "main" java.awt.HeadlessException
at java.applet.Applet.<init>(Applet.java:67)
at javax.swing.JApplet.<init>(JApplet.java:130)
at com.glavsoft.viewer.Viewer.<init>(Viewer.java:67)
at com.glavsoft.viewer.Viewer.<init>(Viewer.java:75)
at com.glavsoft.viewer.Viewer.main(Viewer.java:53)
After some searching I found out install OpenJDK Java runtime can solve this problem.
sudo apt-get install openjdk-7-jre