Jamieson, Fausset and Brown on Jeremiah 22:19

19. burial of an ass--that is, he shall have the same burial as an ass would get, namely, he shall be left a prey for beasts and birds [Jerome]. This is not formally narrated. But 2Ch 36:6 states that "Nebuchadnezzar bound him in fetters to carry him to Babylon"; his treatment there is nowhere mentioned. The prophecy here, and in Jr 36:30, harmonizes these two facts. He was slain by Nebuchadnezzar, who changed his purpose of taking him to Babylon, on the way thither, and left him unburied outside Jerusalem. 2Ki 24:6, "Jehoiakim slept with his fathers," does not contradict this; it simply expresses his being gathered to his fathers by death, not his being buried with his fathers (Psa 49:19). The two phrases are found together, as expressing two distinct ideas (2Ki 15:38; 16:20).