java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Enum

Question

I get this error while trying to persist an entity 'UserAccount' into the database table.

@Entity
@Table(name = "user_account")
public class UserAccount extends BaseEntity {

  @OneToMany(cascade = CascadeType.ALL)
  @JoinColumn(name = "useraccount_id")
  @MapKeyEnumerated(EnumType.STRING)
  private Map<PhoneType, PhoneNumber> phones = new HashMap<PhoneType, PhoneNumber>();

  //... other attributes
  //... default constructor, getters and setters
}

public enum PhoneType {
  HOME("home"),
  MOBILE("mobile"),
  FAX("fax"),
  WORK("work");

  private String value;

  PhoneType(String value) {
     this.value = value;
  }

  @JsonValue
  public String getValue() {
      return value;
  }
}

@Entity
@Table(name = "phone_number")
public class PhoneNumber extends BaseEntity {

  private String areaCode;
  private String number;

  //... default constructor, getters and setters
}

and finally..

public class UserAccountRepository {

    @Inject
    EntityManager entityManager;

    @Override
    public UserAccount save(UserAccount userAccount) {
        if (userAccount.getId() == null) {
            entityManager.persist(userAccount);
        } else {
            userAccount = entityManager.merge(userAccount);
        }
        return userAccount;
    }

  //.. other methods
}

Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Enum
    at org.eclipse.persistence.mappings.converters.EnumTypeConverter.convertObjectValueToDataValue(EnumTypeConverter.java:165)
    at org.eclipse.persistence.mappings.foundation.AbstractDirectMapping.extractIdentityFieldsForQuery(AbstractDirectMapping.java:568)
    at org.eclipse.persistence.internal.queries.MappedKeyMapContainerPolicy.getKeyMappingDataForWriteQuery(MappedKeyMapContainerPolicy.java:145)
    at org.eclipse.persistence.mappings.OneToManyMapping.updateTargetRowPostInsertSource(OneToManyMapping.java:1425)
    at org.eclipse.persistence.mappings.OneToManyMapping.performDataModificationEvent(OneToManyMapping.java:936)
    at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsWithChangeSet(CommitManager.java:162)
    at org.eclipse.persistence.internal.sessions.AbstractSession.writeAllObjectsWithChangeSet(AbstractSession.java:4387)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase(UnitOfWorkImpl.java:1493)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1583)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.issueSQLbeforeCompletion(UnitOfWorkImpl.java:3258)
    at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.issueSQLbeforeCompletion(RepeatableWriteUnitOfWork.java:357)
    at org.eclipse.persistence.transaction.AbstractSynchronizationListener.beforeCompletion(AbstractSynchronizationListener.java:160)
    at org.eclipse.persistence.transaction.JTASynchronizationListener.beforeCompletion(JTASynchronizationListener.java:70)
    at com.sun.enterprise.transaction.JavaEETransactionImpl.commit(JavaEETransactionImpl.java:452)
    ... 94 more

Other questions with same error suggest to add @Enumerated(EnumType.STRING) on the attribute of type Enum, I have used @MapKeyEnumerated(EnumType.STRING) on the phones Map, but I still see get this error. Any clues where am I wrong?

Please let me know if I haven't asked the question as per the SO guidance, I will correct it (as this is my 1st question).

score 3 · Answer 1 · answered Apr 16 '20 at 09:10

I made a change to the PhoneNumber class as below

@Entity
@Table(name = "phone_number")
public class PhoneNumber extends BaseEntity {

  private PhoneType type;
  private String areaCode;
  private String number;

  //... default constructor, getters and setters
}

and then added @MapKey(name = "type") in the UserAccount as below.

@OneToMany(cascade = CascadeType.ALL)
    @JoinColumn(name = "useraccount_id")
    @MapKeyEnumerated(EnumType.STRING)
    @MapKey(name = "type")
    private Map<PhoneType, PhoneNumber> phones = new HashMap<PhoneType, PhoneNumber>();

With these changes I am now able to save the UserAccount object successfully into the db tables.

java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Enum

1 Answers1