Springboot + MySQL:no se puede leer ningún tipo de fecha de (DATE, DATETIME, TIMESTAMP) MySQL

Hice una configuración de prueba con sus clases y debería estar funcionando :) Espero que esto sea útil.

aplicación.propiedades

spring.datasource.url=jdbc:mysql://localhost:3306/forum_demo?useUnicode=true&characterEncoding=utf8
spring.datasource.username=testuser
spring.datasource.password=testuser
#mybatis.config-location=classpath:mybatis-config.xml
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql = true

Comentario.java

package stackoverflow;

import java.sql.Timestamp;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class Comment {

@Id
@GeneratedValue
private int id;
private String content;
private int userId;
/* I tried java.util.Date here as well for DATETIME in MYSQL, it is the same result*/
private Timestamp createDate;
private int entityId;
private int entityType;
private int status;
public int getId() {
  return id;
}
public void setId(int id) {
  this.id = id;
}
public String getContent() {
  return content;
}
public void setContent(String content) {
  this.content = content;
}
public int getUserId() {
  return userId;
}
public void setUserId(int userId) {
  this.userId = userId;
}
public Timestamp getCreateDate() {
  return createDate;
}
public void setCreateDate(Timestamp createDate) {
  this.createDate = createDate;
}
public int getEntityId() {
  return entityId;
}
public void setEntityId(int entityId) {
  this.entityId = entityId;
}
public int getEntityType() {
  return entityType;
}
public void setEntityType(int entityType) {
  this.entityType = entityType;
}
public int getStatus() {
  return status;
}
public void setStatus(int status) {
  this.status = status;
}


}

ComentarioRepo.java

package stackoverflow;

import org.springframework.data.repository.CrudRepository;

public interface CommentRepo extends CrudRepository<Comment, Integer> {

}

Cargador de comentarios.java

package stackoverflow;

import java.sql.Timestamp;
import java.util.Calendar;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.stereotype.Component;

@Component
public class CommentLoader implements ApplicationListener<ContextRefreshedEvent> {

    @Autowired
    CommentRepo commentRepo;

    @Override
    public void onApplicationEvent(ContextRefreshedEvent event) {
        Calendar cal = Calendar.getInstance();
        Comment comment = new Comment();
        comment.setContent("some conetent");
        comment.setCreateDate(new Timestamp(cal.getTimeInMillis()));
        comment.setStatus(1);
        Comment savedComment = commentRepo.save(comment);

        Comment comment2 = commentRepo.findOne(savedComment.getId());
        System.out.println("Datum : " + comment2.getCreateDate());
    }       
}