code: protected String getApparentVersion(String jarName, long jarSize)
    {
      // If we found a matching size and it's for our 
      //  jar, then return it's description
      // Lookup in static jarVersions Hashtable
      String foundSize = (String) jarVersions.get(new Long(jarSize));
  
      if ((null != foundSize) && (foundSize.startsWith(jarName)))
      {
        return foundSize;
      }
      else
      {
        if ("xerces.jar".equalsIgnoreCase(jarName)
                || "xercesImpl.jar".equalsIgnoreCase(jarName))
  //              || "xalan.jar".equalsIgnoreCase(jarName))
        {
  
          // For xalan.jar and xerces.jar/xercesImpl.jar, which we ship together:
          // The jar is not from a shipped copy of xalan-j, so 
          //  it's up to the user to ensure that it's compatible
          return jarName + " " + WARNING + CLASS_PRESENT;
        }
        else
        {
  
          // Otherwise, it's just a jar we don't have the version info calculated for
          return jarName + " " + CLASS_PRESENT;
        }
      }
    }
docs: Cheap-o method to determine the product version of a .jar.
  
  Currently does a lookup into a local table of some recent
  shipped Xalan builds to determine where the .jar probably
  came from.  Note that if you recompile Xalan or Xerces
  yourself this will likely report a potential error, since
  we can't certify builds other than the ones we ship.
  Only reports against selected posted Xalan-J builds.
  
  //@todo actually look up version info in manifests
  
  @param jarName base filename of the .jarfile
  @param jarSize size of the .jarfile
  
  @return String describing where the .jar file probably
  came from