Green’s Dictionary of Slang

Jack the Jew n.

also Jew-Jack
[racial stereotyping]

a receiver of stolen goods, usu. of the least valuable type.

[UK]‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 102: Jack the Jew, or Jew-Jack an Israelite who acquires the nickery of Jack, is either a thief or a receiver of stolen goods ? of the lowest order.