J's skin is a polymer. Antonia developed it for durability and a natural look. That it feels like human skin is another advantage she gave it. She can't share her development, because it would be illegal for anyone else in Jewde to use it. And she won't share it anyway, because it is J and he is hers. Antonia knows everything about J: the metal of his bones, the precise amount of stress his joints can take.
They call him her experiment, her father, her magnum opus. When they think she is not listening they call him other things. Daisuke says Antonia is J's goddess; he may have heard that from J himself. It is all true, and none of it; the truth blurs for humans and even for machines.
Inside J's head there are more connections than she can count, but though she formed and programmed him she does not know everything, cannot predict every word or wink of his eye. She tells herself that makes him more than a machine, more than a conglomeration of desires and memories. And more than the harsher words whispered behind her back.
And yes, she knows what it is like to have him hold her close and speak softly into her ear. This is not what she programmed him for, though perhaps it is part of why she strove to give him a semblance of will. His hands are warm, if only where they touch her; his lips are soft, if only because she created them so.
Every night she sleeps in the laboratory, because J is there. Only to herself does she use the word love, and she still isn't certain what it means.
J reads her stories; he tells her his own tales about fighting crime in Jewde. He shows her the bullet holes and she fixes them. When he comes home bent and broken into a hulk of metal she curses Daisuke and fixes that too.
A cyborg could have far more time than any of them, but he doesn't, not when his nature is outlawed and his partner saves a bullet for him. Antonia tells herself that she accepts that, and tells J too. Her lies are the same as truth to him.