J-Resolved spectra is one of the original 2D experiments. It suffered from poor lineshape and sensitivity but processing improvements (backwards linear prediction) have made this experiment very useful.  In a 2D J-Resolved spectrum, the X axis is a normal 1D proton, while the Y axis gives a multiplet with the separation equal to the coupling.  Shown below is J-Resolved spectrum for sucrose. The red oval shows the doublet for the anomeric proton. The J coupling can be read directly off the Y axis.

J-Resolved spectrum