Not his natural son, for he was his uncle, 2 Kings 24:17; but his legal son, or his successor, upon whom the son's right was devolved by virtue of that law, Numbers 27:8-10, and therefore it is not strange if he have the name of son with it. See Poole on "Luke 3:1". Or this was another Zedekiah; because it is improbable, and without example, that one and the same man should be twice mentioned in the same genealogy as the son of two several parents.
Related Commentaries of 1 Chronicles 3:16
1 Chronicles 3:16
16 And the sons of Jehoiakim: Jeconiahi his son, Zedekiah his son.