title: Spring Reactive with Oracle ClassCastException
body: <p>Hi trying springboot reactive using Oracle DB.
  i got this exception when i trying to save the <em>User</em>.
  anyone has any idea why?
  i verified that connection is established</p>
  <pre><code>val u = Users(&quot;123&quot;, &quot;123&quot;, &quot;123&quot;)
  usersRepository.save(u).subscribe { it -&gt; println(it.email) }
  </code></pre>
  <p>This is my Repository</p>
  <pre><code>@Repository
  interface UsersRepository : ReactiveCrudRepository&lt;Users, String&gt; {
      
  }
  </code></pre>
  <p>This is the Users class</p>
  <pre><code>@Table(name = &quot;users&quot;)
  class Users(user: String?, email: String?, pass: String?) {
      constructor() : this(null, null, null ) {
  
      }
  
      @Id
      @Column
      var username: String? = user
  
      @Column
      var email: String? = email
  
      @Column
      var password: String? = pass
  
      @Column
      var resetUuid: String? = null
  
      @Column
      var expiryDatetime: LocalDateTime? = null
  }
  </code></pre>
  <p>the DDL</p>
  <pre><code>CREATE TABLE &quot;USERS&quot; 
     (    &quot;USERNAME&quot; VARCHAR2(255 CHAR) NOT NULL ENABLE, 
      &quot;EMAIL&quot; VARCHAR2(255 CHAR), 
      &quot;EXPIRY_DATETIME&quot; TIMESTAMP (6), 
      &quot;PASSWORD&quot; VARCHAR2(255 CHAR), 
      &quot;RESET_UUID&quot; VARCHAR2(255 CHAR), 
       PRIMARY KEY (&quot;USERNAME&quot;))
  </code></pre>
  <p>this the exception</p>
  <pre><code>reactor.core.Exceptions$ErrorCallbackNotImplemented: java.lang.ClassCastException: class java.lang.Long cannot be cast to class java.lang.Integer (java.lang.Long and java.lang.Integer are in module java.base of loader 'bootstrap')
  Caused by: java.lang.ClassCastException: class java.lang.Long cannot be cast to class java.lang.Integer (java.lang.Long and java.lang.Integer are in module java.base of loader 'bootstrap')
      at java.base/java.util.stream.Collectors.lambda$summingInt$19(Collectors.java:681) ~[na:na]
      at reactor.core.publisher.MonoStreamCollector$StreamCollectorSubscriber.onNext(MonoStreamCollector.java:132) ~[reactor-core-3.4.22.jar:3.4.22]
      at reactor.core.publisher.FluxFlatMap$FlatMapMain.tryEmit(FluxFlatMap.java:543) ~[reactor-core-3.4.22.jar:3.4.22]
      at reactor.core.publisher.FluxFlatMap$FlatMapInner.onNext(FluxFlatMap.java:984) ~[reactor-core-3.4.22.jar:3.4.22]
      at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:200) ~[reactor-core-3.4.22.jar:3.4.22]
      at reactor.core.publisher.FluxConcatArray$ConcatArrayDelayErrorSubscriber.onNext(FluxConcatArray.java:364) ~[reactor-core-3.4.22.jar:3.4.22]
      
      
  </code></pre>