In one aspect, an adhesive dispensing system 30 includes a dispensing module 32 having an inlet and an outlet, a supply 35 of hot melt adhesive maintained at low pressure, and a low pressure liquid passageway 44 communicating between the supply 35 and the inlet of the dispensing module 32. Liquid material is received through the inlet at a low pressure, and the dispensing module 32 rapidly develops high pressure at the outlet 78 to jet the liquid material from the outlet 78. In another aspect, an apparatus for jetting liquid material includes a dispenser body 38 having a liquid chamber 40. A piston 54 is movably disposed within the liquid chamber 40, from a position wherein a piston tip 58 is spaced from a complimentary shaped recess 76, to a position wherein the piston tip 58 effectively seals off the recess 76, then to a position wherein the piston tip 58 is received within the recess 76 to displace a discrete volume of liquid material from the recess 76.