John Gill's  Exposition of the Bible 

2 Samuel 3:4

And the fourth, Adonijah the son of Haggith; and the fifth, Shephatiah the son of Abital;

And the fourth, Adonijah the son of Haggith,.... The same that usurped the throne before his father's death, to anticipate Solomon, and died by his order, 1 Kings 1:5;

and the fifth, Shephatiah the son of Abital; of whom we read nowhere else.