I have written a code in Java to read multiple documents in bulk from a Bucket in CouchBase. I have made it functional somehow, but I don't understand how it works.

 I'm making my project on NetBeans IDE. I copied this code from some website and made it work somehow. I am completely new to CouchBase and kinda okay with java. But I don't understand anything about CouchBase and it's API.

Here, appbucket is my Bucket in CouchBase.

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```
    List<String> docIds = new ArrayList<>();

    List<JsonDocument> docFromCouch = Observable
        .from(docIds)
 .retryWhen(RetryBuilder.anyOf(IllegalStateException.class).max(retries).delay(Delay.linear(TimeUnit.SECONDS,timeout)).build())
        .flatMap(appbucket.async()::get)
        .toList()
        .toBlocking()
        .single();
```

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This is from my pom.xml file. I don't understand this as well except this is the jar file which enables us to use certain functions.
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```
    <groupId>com.couchbase.client</groupId>
    <artifactId>java-client</artifactId>
    <version>2.7.7</version>
          <type>jar</type>
```

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Although I tried to understand what these functions do and how from CouchBase Docs, but as I said I'm a newbie and all those things went over my head.
Explanation for each function is really needed. Thanks a lot guys.