Creating extra column with OneToOne annotation

I have an user object and I need to load group object along with the user object.

I have written for that the following code.

@Entity
@Table(name = "User_info")
public class UserDao {
   @Id
   @GeneratedValue(strategy = GenerationType.AUTO)
   private int userId;

   @Column(name="first_name")
   private String firstName;

   @Column(name="groupId")
   private int groupId;
        
   @OneToOne(cascade = CascadeType.ALL)
   @PrimaryKeyJoinColumn
   private GroupMaster groupMaster;
    
   //setters and getters
}

and GroupMaster:

@Entity
@Table(name = "group_master")
public class GroupMaster {

  	@Id
  	@GeneratedValue(strategy = GenerationType.AUTO)
   	private int groupId;

   	@Column(name="groupName")
   	private String groupName;
    
    //Setters and getters
}

Here the group_master is the master table and it has groupId and groupname.

I will give the groupId in user_info table based on that value I need to get the groupMaster object. But the problem here is hibernate is creating

CREATE TABLE group_master
(
    group_id integer NOT NULL,
    group_name character varying(255),
    user_user_id integer NOT NULL,

    CONSTRAINT group_master_pkey PRIMARY KEY (group_id ),
    CONSTRAINT fkjxrn8rglp972s1pqfh5tsb6cu FOREIGN KEY (user_user_id)
       REFERENCES user_info (user_id) MATCH SIMPLE
       ON UPDATE NO ACTION ON DELETE NO ACTION
)
WITH ( OIDS=FALSE );

ALTER TABLE group_master OWNER TO XYZ;

I don't know why it creates user_user_id column. I don't have any use with this user_user_id column. The relation should be with groupId. How can I fix it.

You don't need a separate groupId-column or the @PrimaryKeyJoinColumn Annotation
Change your UserDao to:

@Entity
@Table(name = "User_info")
public class UserDao {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int userId;
    @Column(name="first_name")
    private String firstName;
    
    @OneToOne(cascade = CascadeType.ALL)
    private GroupMaster groupMaster;

 //setters and getters
}

you should define the @OneToOne relationship in both sides so you need to add the @OneToOne annotation to the GroupMaster too, to make it in the properly way you should do it like this :

@Entity
@Table(name = "User_info")
public class UserDao {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int userId;
    @Column(name="first_name")
    private String firstName;

    @OneToOne(mappedBy = "user")
    GroupMaster group;

 //setters and getters
}

then the GroupMaster Entity should be like this :

 @Entity
    @Table(name = "group_master")
    public class GroupMaster {
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
        private int groupId;
        @Column(name="groupName")
        private String groupName;
       
        @OneToOne
        @PrimaryKeyJoinColumn
        UserDao user;

        //Setters and getters
    }