I haven't spawned an external command from Java in a very long time, but I'm not entirely certain that the command didn't execute.
You have a process "start" command followed by a bunch of stuff that affects stdio redirection, and I'm suspecting that the command is running and completing before you've set up the channels to receive the output, so the output is falling out into the Twilight Zone. Just a guess, though.
Some people, when well-known sources tell them that fire will burn them, don't put their hands in the fire.
Some people, being skeptical, will put their hands in the fire, get burned, and learn not to put their hands in the fire.
And some people, believing that they know better than well-known sources, will claim it's a lie, put their hands in the fire, and continue to scream it's a lie even as their hands burn down to charred stumps.