Well, there weren’t any “Jews” at that time. Judah was his great grandson, as I’m sure your already know.
Abraham had Issac, Isaac had Jacob and Jacob had 12 sons by four different women. Jacob wrestled with God at a creek at night and refused to let Him go unless He blessed him. God changed Jacob’s name to Israel (one who strives with God) and his twelve sons became the 12 tribes of Israel, Judah being one of them. When they came into Canaan each tribe received certain lands to settle.
Fast forward a few hundred years or so and the kingdom of Israel is split in two after Solomons reign with the northern ten tribes and the two southern tribes of Judah and Benjamin.
The northern tribes are carried into Assyrian captivity and disappear from history. Benjamin is very small and is essentially absorbed by Judah in the south. And this “Judah” becomes symbolic of the nation of Israel,
The term “Jew” may have been a shortened version of Hebrews or Judah, depending on who you ask.
There, that’s probably much more than you expected.
Peace to you