Yes, most people know me as "P.J. Healy", even though I use my
full name ("Paul J. Healy") for publishing and other official business.

The J. stands for Jay.

If you'd like, you can call me P. Jay Healy.

Homer Simpson has the same middle name:
Homer's middle name, "Jay," is a tribute by Simpsons creator Matt Groening to the work of cartoon producer Jay Ward, creator of Bullwinkle J. Moose and Rocket J. Squirrel.