title: Failed to convert request element in entity with @IdClass
body: <p>I have the following setup:</p>
  
  <pre><code>@Entity
  @IdClass(MemberAttributePk.class)
  public class MemberAttribute {
      @Id
      @ManyToOne @JoinColumn(name="member_id")
      protected Member member;
  
      @Id
      protected String name;
  
      private String value;
  
      public MemberAttribute() {}
  
      // get &amp; set
  }
  </code></pre>
  
  <p>And the id class:</p>
  
  <pre><code>public class MemberAttributePk implements Serializable {
      protected Member member;
      protected String name;
  
      public MemberAttributePk() {}
  
      // get &amp; set
  }
  </code></pre>
  
  <p>I have defined a simple Spring Data repository for <code>MemberAttribute</code>:</p>
  
  <pre><code>@Repository
  public interface MemberAttributeRepo extends JpaRepository&lt;MemberAttribute, MemberAttributePk&gt; {
  }
  </code></pre>
  
  <p>Now, all I want to do is persist a member attribute to the database:</p>
  
  <pre><code>public void saveAttribute(Member member, String name, String value) {
      MemberAttribute attr = new MemberAttribute(member, name, value);
      attributeRepo.save(attr);
  }
  </code></pre>
  
  <p>However, I end up with this server exception:</p>
  
  <pre><code>2016-08-28 00:24:20.673  WARN 5656 --- [nio-8080-exec-8] .w.s.m.s.DefaultHandlerExceptionResolver : 
  Failed to convert request element: org.springframework.beans.ConversionNotSupportedException: 
  Failed to convert property value of type [java.lang.Long] to required type [com.example.Member] for property 'member'; nested exception is java.lang.IllegalStateException: 
  Cannot convert value of type [java.lang.Long] to required type [com.example.Member] for property 'member': 
  no matching editors or conversion strategy found
  </code></pre>
  
  <p>Any idea what am I doing wrong?
  Thanks!</p>