In the time of Bible history there was a geographic region known as Judea, Judea was a province of the Roman empire, people who lived in the region of Judea were known as the Judeans, in Latin it was iudeas, and in greek it was Ioudaios. In Latin and greek there was not a letter "J". The first bibles were written in Latin and greek, the word jew never appeared in any of them. Judea was the country and Judeans were the people and Jesus was referred to only as a Judean.
It was not until the year 1345 that a man named John Wycliffe translated the bible into english.
There was no english edition of the bible before that, because no one could read, only the church people could read latin and greek. So in this new bible, there had to be an english word for Judean, but there was none since Judea didn't exist anymore. So in the earlier translations he used the word "gyu" to refer to Jesus and the people of Judea. Between 1345 and the 17th century, there was no printing press, but after the printing press was invented, the word passed through many changes including: giu, iu (the i in Latin is pronounced like a j like Julius Ceasar), iuw, ieuu, ieuy, iwe, iow, iewe, ieue, iue, ive, iew, and finally in the 18th century jew. All of these a corrupted form of the original. There was no such word as jew before that.
The so called jews are eastern Europeans that converted to talmudism. There was no such thing as judaism before that.