title: org.hibernate.AnnotationException: mappedBy reference an unknown target entity property
body: <p>I am trying to make a OneToMany relationship between User and Project but I am getting following error: </p>
  
  <pre><code>org.hibernate.AnnotationException: mappedBy reference an unknown target entity property: ProjectDTO.FKUser in UserDTO.projectDTOs
  </code></pre>
  
  <p>My User class look like below</p>
  
  <pre><code>@Entity
  @Table(name = "USER")
  public class UserDTO implements java.io.Serializable {
  
      private Integer iduser;
      private Set&lt;ProjectDTO&gt; projects = new HashSet&lt;ProjectDTO&gt;(0);;
  
      public UserDTO() {
      }
  
      @Id
      @GeneratedValue(strategy = IDENTITY)
      @Column(name = "IDUser", unique = true, nullable = false)
      public Integer getIduser() {
          return this.iduser;
      }
  
      @OneToMany(fetch = FetchType.LAZY, mappedBy = "FKUser")
      public Set&lt;ProjectDTO&gt; getProjectDTOs() {
          return projects;
      }
  
  }
  </code></pre>
  
  <p>And my Project class looks like</p>
  
  <pre><code>@Entity
  @Table(name = "Project")
  public class ProjectDTO implements java.io.Serializable {
  
      private Integer idproject;
      private UserDTO FKUser;
  
      public ProjectDTO() {
      }
  
      @Id
      @GeneratedValue(strategy = IDENTITY)
  
      @Column(name = "IDProject", unique = true, nullable = false)
      public Integer getIdproject() {
          return this.idproject;
      }
  
      @ManyToOne(fetch = FetchType.LAZY)
      @JoinColumn(name = "FKUser", referencedColumnName = "IDUser")
      public UserDTO getUserDTO() {
          return FKUser;
      } 
  }
  </code></pre>
  
  <p>I went through some similar questions but I was unable to figure out where I was going wrong. Maybe I am missing something very obvious. </p>
  
  <p>Thanks a lot</p>