A 31-year-old former New Jersey man will spent years in federal prison after admitting he threatened politicians, judges, lawyers and police officers. Eric G. Hafner pleaded guilty Tuesday to making threatening communications with intent to extort, making threatening communications in interstate or foreign commerce and conveying false information concerning the use of an explosive device, the U.S. Attorney’s Office for New Jersey said. Hafner, who made the threats from July 2016 to May 2018 while living abroad, is scheduled to be sentenced Sept. 21. The former Monmouth County resident threaten…