final ConcurrentMap<String, GridGainState> states = new ConcurrentHashMap<>();
G.addListener(new GridGainListener() {
@Override public void onStateChange(@Nullable String name, GridGainState state) {
if (state == STARTED) {
GridGainState state0 = states.put(maskNull(name), STARTED);
assert state0 == null;
}
else {
assert state == STOPPED;