The following is a description of the JARs included with JDOM.  
More information about the JARs can be found by reading the files 
accompanying the JARs.  Note that the build scripts (build*) take
care of adding the proper JARs to the path for building.  However
you need to set your classpath properly for runtime execution.

ant.jar
  Used for building JDOM.

collections.jar
  Needed only if building JDOM on JDK 1.1.  Not needed for JDK 1.2.  Do not
  put this in your classpath if you're using JDK 1.2.

xerces.jar
  An XML parser you can use with JDOM.  It's very popular but doesn't have 
  JAXP 1.1 support and it has a large JAR footprint.  Use this parser if you 
  don't care about XSLT transforms.  It's the default if no other parsers 
  are in your classpath.

crimson.jar
  Another XML parser you can use with JDOM.  It has JAXP 1.1 support and a 
  relatively small JAR.  Use this parser if you're doing transforms or want
  a small footprint.  It's the default JAXP parser, so JDOM will use Crimson
  if you have jaxp.jar and this JAR in your classpath.

jaxp.jar
  The Java API for XML Processing containing javax.xml.* classes.  Put this 
  in your classpath if you're doing XSLT transforms.

xalan.jar
  An XSLT processor.  Put this in your classpath if you're doing transforms.

