JPA - Copy data between 2 different entities with a common superclass

Question

I have a situation like this

@MappedSuperclass
public class BaseEntity {

   @Column(name = "COL_1)
   private String column1;

   @Column(name = "COL_2)
   private String column2;
}

@Entity
@Table(name = "TABLE_A")
public class EntityA extends BaseEntity {
   @Id
   private Long idA;
}

@Entity
@Table(name = "TABLE_B")
public class EntityB extends BaseEntity {
   @Id
   private Long idB;
}

Having an instance of EntityA, what I want is to create a new instance of EntityB with all the attribute inherited from superclass "copied" from the instance of EntityA, exept the EntityB specific ones.

There is a "smart" way to do this WITHOUT doing each single set/get?

N.B. The code above is just one example, in my real case the superclass has over 100 attributes...

Answer 1

Apache Beanutils library has such functionality.

https://commons.apache.org/proper/commons-beanutils/apidocs/org/apache/commons/beanutils/BeanUtils.html#copyProperties-java.lang.Object-java.lang.Object-

package test;

import java.lang.reflect.InvocationTargetException;
import org.apache.commons.beanutils.BeanUtils;

...
EntityA instanceA = ...
EntityB instanceB = ...
BeanUtils.copyProperties(instanceB, instanceA);
  // exceptions are thrown when some negative situation occur.
  // I have no knowledge r/o property (having only getter) is not set / thow exception

  //You should review, how this automatic task is executed in Your scenario. But it is auto 

...persist(instanceB);