public static Collection<Class<?>> getClassNamesFromConfig(HiveConf hiveConf, ConfVars confVar) {
    String[] classNames = org.apache.hadoop.util.StringUtils.getStrings(HiveConf.getVar(hiveConf,
        confVar));
    if (classNames == null) {
      return Collections.emptyList();
    }
    Collection<Class<?>> classList = new ArrayList<Class<?>>(classNames.length);
    for (String className : classNames) {
      if (StringUtils.isEmpty(className)) {
        continue;
      }
      try {
        classList.add(Class.forName(className));
      } catch (Exception ex) {
        LOG.warn("Cannot create class {} for {} checks", className, confVar.varname);
      }
    }
    return classList;
  }
Sets up the job so that all necessary jars ar passed that contain classes from the given argument of this method.
@param conf jobConf instance to setup
@param classes the classes to look in jars for
@throws IOException
ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java