I left out one important point. That is to copy the ant/dist/lib files to your ant/lib dir so the revised FAQ entry would look like: This should go in the FAQ: Question: I cannot building struts, I keep getting either a java.lang.ClassNotFoundException: org.apache.tools.ant.taskdefs.optional.TraXLiaison or a java.lang.SecurityException: sealing violation I played with my adjusted my class paths for 5 hours, Help ... what can I do ? Answer: I would recommend ALWAYS building 'ant' before trying to build 'struts' for the first time. Why? It seems that ant customizes itself for each environment, and determines which XML parser you are using. Once I did that struts builds without a hitch. 1) Read the Build instructions for ANT, creating the ANT_HOME, and other needed enviromental variables. 2) Then run build.bat - to perform the bootstrap build of ant and build the final version of Ant. 3) Copy the ANT_HOME/dist/lib jar files to ANT_HOME/lib . 4) Make sure you read the 'struts' build guide, and have installed all required packages. 5) Change to the struts directory. 5) Then type 'build' If this doesn't work then make sure that your CLASSPATH references only one jaxp.jar and that parser.jar isn't in your CLASSPATH