Mixing sync and async giving problems

Java SDK
2

You are doing blocking calls inside a non-blocking async stream, in a map function. That’s a bad idea©

You can use sync bucket in parallel to an async bucket, separately, but mixing the two together isn’t possible and will lead to blocking and timeouts, as you saw.

What I mean by separately is more along the lines of:

//this is OK
JsonObject updatedContent = JsonObject.emtpy(); //or something more relevant
JsonDocument docUpdated = JsonDocument.create("key1", updatedContent);
aBucket.upsert(docUpdated).subscribe(); //we just update in a fire and forget fashion

JsonDocument otherDoc = bucket.get("key2"); //do something with the other doc

As a side note, on your test you could have directly used get without Observable.just (for a single key):

Observable<Object> ob = aBucket.get(key)
   //still a bad idea
   .map(o -> adjustDoc(o));