Has Spring-boot changed the way auto-increment of ids works through @GeneratedValue? : <p>Spring-Boot <strong>2.0.0</strong> seems to have modified the way <strong>Hibernate</strong> is auto configured. </p>

<p>Let's suppose two simple and independent JPA entities:</p>

<pre><code>@Entity
class Car {
   @Id
   @GeneratedValue
   private long id;
   //....
} 

@Entity
class Airplane {
   @Id
   @GeneratedValue
   private long id;
   //....
}
</code></pre>

<p>Prior, using Spring-Boot <strong>1.5.10</strong>, I was able to generate separate sequences of auto-increments, meaning that I can get a <code>Car</code> with <strong>1</strong> as primary key and an <code>Airplane</code> with <strong>1</strong> as primary key too. 
No correlation between them, e.g no shared sequence. </p>

<p>Now, with <strong>2.0.0</strong>, when I sequentially create a very first <code>Car</code> then a very first <code>Airplane</code>, the car gets <strong>1</strong> as id and airplane gets <strong>2</strong>.     </p>

<p>It seems that he has to deal with the <code>GeneratedType.AUTO</code>, that is the "used by default" specified within the <code>@GeneratedValue</code> annotation source.<br>
However, my reasoning seems to stop here since <code>GeneratedType.AUTO</code> was also set as default with the <strong>1.5.10</strong>.</p>

<p>A simple workaround to fulfil my expectation is to specify the <code>IDENTITY</code> strategy type of generation like so:      </p>

<pre><code>@Entity
class Car {
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private long id;
   //....
} 

@Entity
class Airplane {
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private long id;
   //....
}
</code></pre>

<p>I can't figure out an explanation of this behavior. </p>

<p>What has Spring-boot <strong>2.0.0</strong> changed, explaining this scenario?</p>
