To clarify, Judeans, were Israelite inhabitants of Judah, with the word Judean, signifying a person is an inhabitant of Judah.
If you read scripture, you'll note that around 600BC, Judah was conquered by babylon, during which time, the tribes of Judah and Benjamin, with some Levites, who were at that time the inhabitants of Judah, were mostly carried off into slavery to Babylon.
Shortly after, at that time, Edom, a land to the south of Judah, invaded and occupied the weakened Judah and set their own king over Judah.
Their occupation lasts until 70 AD. During the time of their occupation of Judah, the Edomites became known as Jews.
These are the same Jews Christ is speaking with in the Book of John. He tells them, they are of their father the devil, the synagogue of satan, not of his sheep and a lot more.