The ornamental design for a jar, as shown and described.
FIG. 1 is a perspective view of a jar embodying my new design;
FIG. 2 is a front elevational view;
FIG. 3 is a top plan view thereof.
The rear elevational view of the jar, not shown, is identical to the front
elevational view shown in FIG. 2. The jar is the same in appearance when
viewed from any side.