List<Configurable> (@NotNull DebuggerSettingsCategory category, List<DebuggerConfigurableProvider> providers) { List<Configurable> configurables = null; for (DebuggerConfigurableProvider provider : providers) { Collection<? extends Configurable> providerConfigurables = provider.getConfigurables(category); if (!providerConfigurables.isEmpty()) { if (configurables == null) { configurables = new SmartList<>(); } configurables.addAll(providerConfigurables); } } return ContainerUtil.notNullize(configurables); }