code: public void setClassPath(Path classpath) {
          pathComponents.removeAllElements();
          if (classpath != null) {
              Path actualClasspath = classpath.concatSystemClasspath("ignore");
              String[] pathElements = actualClasspath.list();
              for (int i = 0; i < pathElements.length; ++i) {
                  try {
                      addPathElement(pathElements[i]);
                  } catch (BuildException e) {
                      // ignore path elements which are invalid
                      // relative to the project
                  }
              }
          }
      }
docs: Set the classpath to search for classes to load. This should not be
  changed once the classloader starts to server classes
  
  @param classpath the search classpath consisting of directories and
  jar/zip files.