It happened at the store on Springfield Road in Union.
Police got a call just before 11 a.m. Thursday from a person who saw a man wearing a mask and armed with what appeared to be a gun inside the store.
Employees got customers out of the store while multiple agencies responded. No gun was found and the store reopened Thursday afternoon.
According to police, 20-year-old Joshua Phillips, of Newark, turned himself in to police Thursday night.
The Union County prosecutor’s office says the gun witnesses saw Phillips carrying was actually a large black airsoft gun. Phillips allegedly took the gun out of its packaging in the store.
The incident happened just 12 days after a lone gunman killed 22 people at a Walmart in El Paso, Texas.