DTO and Entity in one object?

I am currently in a dilemma and I've been reading stuff regarding this.

I am making my DTOs be also my Entities. It looks something like this:

@Entity
@PasswordMatches // custom validator
public class User {

    @Id
    @Column
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long id;

    @Column
    @NotNullOrEmpty // custom validator
    private String password;

    @Transient
    @NotNullOrEmpty // custom validator
    private String confirmPassword;

Q1: Is this acceptable or is there any better way of doing this? Because currently, before saving a User I am hashing the password for obvious reasons but if I em.persist(user) directly, it will fail because of @PasswordMatches is failing. It's only saving when I do user.setConfirmPassword(hashedPassword) just to satisfy the validation. Am I doing the right thing here?