Military compensation comes in two broad forms: pay and allowances. As a rule of thumb, pay is taxable but allowances aren't, although hazardous duty or combat pay can be tax free under certain circumstances.

Because Justin is single and perhaps living in the barracks*, some of these allowances may not apply to him. For military personnel who live off base, they get a tax-free housing allowance. There's also a tax-free Variable Housing Allowance to compensate for high cost of living areas, such as my son in San Diego. They can also get Basic Allowance for Subsistance (BAS) to pay for their food, at least up to a point. If they then eat in the chow hall*, they have to pay for the meal.

*Call me old fashioned, but I refuse to call them dorms - barracks are for military personnel, dorms are for college students. Likewise, its a chow hall or mess hall, not some mealy mouthed PC or ad-man-wannabe speak like "dining facility."