


Hibernate One-To-Many Mapping Error: "Could not Determine Type for: java.util.List"
In Hibernate, handling One-To-Many relationships requires careful mapping configurations. This error typically occurs when the mapping annotations are incorrectly placed or configured.
Analyzing the provided code, we encounter the below error:
org.hibernate.MappingException: Could not determine type for: java.util.List, at table: College, for columns: [org.hibernate.mapping.Column(students)]
This error indicates that Hibernate is unable to determine the type of the students property in the College class. According to the provided mapping, the students property is annotated with @OneToMany and is of type List
Correct Annotation Placement
In field access strategy, which is determined by the @Id annotation, JPA annotations should be placed right above each field instead of getter properties. In this case, the correct annotation placement for the students property is:
@OneToMany(targetEntity=Student.class, mappedBy="college", fetch=FetchType.EAGER) private List<student> students;</student>
Modified College Class
With the annotation placement corrected, the modified College class looks like this:
<code class="java">@Entity public class College { @Id @GeneratedValue(strategy=GenerationType.AUTO) private int collegeId; private String collegeName; @OneToMany(targetEntity=Student.class, mappedBy="college", fetch=FetchType.EAGER) private List<student> students; // Annotation is now placed above the field // Other getters and setters omitted }</student></code>
Conclusion
By correctly placing the @OneToMany annotation above the students field, Hibernate can now properly determine the type of the property and map the One-To-Many relationship between College and Student. This adjustment resolves the "Could not determine type for: java.util.List" error.
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