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== Timoteo Ponce's blog ==
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Get metadata from JPA entities

jpa
I needed to extract a column length from a EJB-JPA Entity configured with annotations, this is how I did it:
import javax.persistence.Column;
import javax.persistence.Entity;

@Entity
public class Person {

@Column(length=30)
private String firstName;

public static void main(String[] args) throws SecurityException, NoSuchFieldException {
Object person = new Person();
println(person.getClass().getDeclaredField("firstName").getAnnotation(Column.class).length());
}
}

Solution source