/**
   * @param ldr Class loader to undeploy.
   * @param recEvt Whether or not to record the event.
   */
  private void undeploy(ClassLoader ldr, boolean recEvt) {
    Collection<GridDeployment> doomed = new HashSet<GridDeployment>();

    synchronized (mux) {
      for (Iterator<LinkedList<GridDeployment>> i1 = cache.values().iterator(); i1.hasNext(); ) {
        LinkedList<GridDeployment> deps = i1.next();

        for (Iterator<GridDeployment> i2 = deps.iterator(); i2.hasNext(); ) {
          GridDeployment dep = i2.next();

          if (dep.classLoader() == ldr) {
            dep.undeploy();

            i2.remove();

            doomed.add(dep);

            if (log.isInfoEnabled()) {
              log.info("Removed undeployed class: " + dep);
            }
          }
        }

        if (deps.isEmpty()) {
          i1.remove();
        }
      }
    }

    for (GridDeployment dep : doomed) {
      if (dep.isObsolete()) {
        // Resource cleanup.
        ctx.resource().onUndeployed(dep);
      }

      if (recEvt) {
        recordUndeploy(dep, true);
      }
    }
  }
  /** @throws Exception If failed. */
  public void testEmptyProjections() throws Exception {
    final GridClientCompute dflt = client.compute();

    Collection<? extends GridClientNode> nodes = dflt.nodes();

    assertEquals(NODES_CNT, nodes.size());

    Iterator<? extends GridClientNode> iter = nodes.iterator();

    final GridClientCompute singleNodePrj = dflt.projection(Collections.singletonList(iter.next()));

    final GridClientNode second = iter.next();

    final GridClientPredicate<GridClientNode> noneFilter =
        new GridClientPredicate<GridClientNode>() {
          @Override
          public boolean apply(GridClientNode node) {
            return false;
          }
        };

    final GridClientPredicate<GridClientNode> targetFilter =
        new GridClientPredicate<GridClientNode>() {
          @Override
          public boolean apply(GridClientNode node) {
            return node.nodeId().equals(second.nodeId());
          }
        };

    GridTestUtils.assertThrows(
        log(),
        new Callable<Object>() {
          @Override
          public Object call() throws Exception {
            return dflt.projection(noneFilter).log(-1, -1);
          }
        },
        GridServerUnreachableException.class,
        null);

    GridTestUtils.assertThrows(
        log(),
        new Callable<Object>() {
          @Override
          public Object call() throws Exception {
            return singleNodePrj.projection(second);
          }
        },
        GridClientException.class,
        null);

    GridTestUtils.assertThrows(
        log(),
        new Callable<Object>() {
          @Override
          public Object call() throws Exception {
            return singleNodePrj.projection(targetFilter);
          }
        },
        GridClientException.class,
        null);
  }