import javax.persistence.Temporal;</BUG>
import javax.persistence.TemporalType;
import javax.validation.constraints.NotNull;
import org.literacyapp.model.BaseEntity;
import org.literacyapp.model.Contributor;
<BUG>@Entity
public class ContributorEvent extends BaseEntity {
</BUG>
@NotNull
@ManyToOne

package org.literacyapp.model.contributor;
import java.util.Calendar;
import javax.persistence.ManyToOne;
import javax.persistence.MappedSuperclass;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.validation.constraints.NotNull;
import org.literacyapp.model.BaseEntity;
import org.literacyapp.model.Contributor;
@MappedSuperclass
public abstract class ContributorEvent extends BaseEntity {
@NotNull
@ManyToOne
