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Reading a serialized object, Tomcat

Dominik Glodzik

Joined: Mar 22, 2011
Posts: 2
Hello everyone,

I seem to have a problem with my JSP application running on Apache Tomcat/6.0.14.

I catch the following exception:
org.apache.jasper.JasperException: javax.servlet.ServletException: java.lang.NoClassDefFoundError: Could not initialize class sun.awt.X11.XToolkit

This happens when I tried to read in a file containing a serialized object.

The class of the object, which is being red, contains an instance of a Swing class ImageIcon. This works fine on GlassFish on my machine, but gives an error when uploaded to Tomcat.

I'd welcome any suggestions how to read in the serialized object.

Stefan Evans

Joined: Jul 06, 2005
Posts: 1018
The server you are running on is a *nix type?
Most probably without a monitor?
Check out headless mode to see if it might help:

I'm not sure if it will or not. The sun.* classes are not really intended for general use
Can you come up with a better approach than serializing java objects?
Dominik Glodzik

Joined: Mar 22, 2011
Posts: 2

thank you VERY much, it works.

Yes, the server runs Linux with no display.

To switch Tomcat to a headless mode, add the following line to
export CATALINA_OPTS=-Djava.awt.headless=true


I agree. Here's the link:
subject: Reading a serialized object, Tomcat