The problem is solved using this line.. @PersistenceCapable(identityType = IdentityType.DATASTORE, detachable = "false") everything else is just fine, thank you for all.
------ SOLUTION ------ package ar.com.app.domain; import java.io.Serializable; import javax.jdo.annotations.IdentityType; import javax.jdo.annotations.PersistenceCapable; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table(name = "USUARIOS") @PersistenceCapable(identityType = IdentityType.DATASTORE, detachable = "false") /** * Clase User * @author Cristian Miranda * @since v0.1 */ public class User implements Serializable { /** * UID */ private static final long serialVersionUID = -4440813061365306611L; @Id @Column(name = "ID") private Integer id; @Column(name = "USERNAME") private String username; @Column(name = "PASSWORD") private String password; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } } -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.