- Preconditions.checkNotNull(key, "key must not be null.");
-
- final T ret = backingTxs.get(key);
- Preconditions.checkArgument(ret != null, "No subtransaction associated with %s", key);
+ final T ret = backingTxs.get(requireNonNull(key, "key must not be null."));
+ checkArgument(ret != null, "No subtransaction associated with %s", key);