Albert Barnes Commentary 2 Samuel 9:12

"And Mephibosheth had a young son, whose name was Mica. And all that dwelt in the house of Ziba were servants unto Mephibosheth." — 2 Samuel 9:12 (ASV)

Mephibosheth was five years old at Saul’s death. He may have been thirteen at David’s accession to the throne of Israel. In the eighth year of David’s reign over all Israel, he would have been twenty-one. His having a son at this time indicates that we are in about the tenth year of David’s reign.

Micha - Or Micah, who, as far as we know, was Mephibosheth’s only son and had a numerous posterity (see marginal references).