title: What is the behavior of the findOne method in MongoOperations in SpringData?
body: <p>I am reading SpringData MongoDB configuration for MongoOperations <a href="http://docs.spring.io/spring-data/mongodb/docs/current/api/org/springframework/data/mongodb/core/MongoOperations.html#findOne-org.springframework.data.mongodb.core.query.Query-java.lang.Class-" rel="nofollow">http://docs.spring.io/spring-data/mongodb/docs/current/api/org/springframework/data/mongodb/core/MongoOperations.html#findOne-org.springframework.data.mongodb.core.query.Query-java.lang.Class-</a></p>
  
  <p>Still do not understand what is the behavior of the findOne method if more than one document satisfies a query:</p>
  
  <pre><code>&lt;T&gt; T   findOne(Query query, Class&lt;T&gt; entityClass)
  </code></pre>