### Question:
StorageContainerManager implements AutoCloseable { @Nullable public StorageContainerInfo getStorageContainer(long groupId) { synchronized (storageContainers) { return this.storageContainers.get(groupId); } } StorageContainerManager(); @Nullable StorageContainerInfo getStorageContainer(long groupId); boolean replaceStorageContainer(long groupId, StorageContainerInfo groupInfo); void removeStorageContainer(long groupId); @Override void close();  }### Answer:
@Test public void testGetNullStorageContainer() { assertNull(manager.getStorageContainer(1234L)); }