void waitForFinish() throws Exception {
    for (Map.Entry<String, Future<Void>> task : tasks.entrySet()) {
      long t1 = System.nanoTime();
      task.getValue().get();
      long t2 = System.nanoTime();
      LOG.debug(task.getKey() + " waited for " + (t2 - t1) + " ns");
    }
  }
Gathers all the jar files necessary to start llap.
llap-server/src/java/org/apache/hadoop/hive/llap/cli/service/LlapTarComponentGatherer.java