if (!sLoaders.contains(cl))
if (cl!=null && !sLoaders.contains(cl))
  public CombinedClassLoader(Collection a_loaders)  {    ArrayList sLoaders = new ArrayList(a_loaders.size());        Iterator iter = a_loaders.iterator();    Object cl;    while (iter.hasNext())      {        cl = iter.next();        if (!sLoaders.contains(cl))          sLoaders.add(cl);      }        loaders = new ClassLoader[sLoaders.size()];    for (int i = 0; i < loaders.length; i++)      loaders[i] = (ClassLoader) sLoaders.get(i);  }