### Question:
RocksdbKVAsyncStore extends AbstractStateStoreWithJournal<RocksdbKVStore<byte[], byte[]>> implements KVAsyncStore<K, V> { @SuppressWarnings("unchecked") @Override public CompletableFuture<Void> init(StateStoreSpec spec) { this.keyCoder = (Coder<K>) spec.getKeyCoder(); this.valCoder = (Coder<V>) spec.getValCoder(); return super.init(spec); } RocksdbKVAsyncStore(Supplier<RocksdbKVStore<byte[], byte[]>> localStateStoreSupplier,
                               Supplier<Namespace> namespaceSupplier); @SuppressWarnings("unchecked") @Override CompletableFuture<Void> init(StateStoreSpec spec); @Override CompletableFuture<V> get(K key); @Override CompletableFuture<Void> put(K key, V value); @Override CompletableFuture<V> putIfAbsent(K key, V value); @Override CompletableFuture<V> delete(K key);  }### Answer:
@Test(expected = NullPointerException.class) public void testInitMissingStreamName() throws Exception { this.streamName = "test-init-missing-stream-name"; StateStoreSpec spec = StateStoreSpec.builder() .name(streamName) .keyCoder(ByteArrayCoder.of()) .valCoder(ByteArrayCoder.of()) .localStateStoreDir(tempDir) .build(); result(store.init(spec)); }