The only thing I can think of is that it’s running on FreeBSD 9.2 within a jail.
openjdk version “1.7.0_25” OpenJDK Runtime Environment (build 1.7.0_25-b15) OpenJDK 64-Bit Server VM (build 23.21-b01, mixed mode)
In fact just testing this on Mac OS X and I don’t get the processes hanging around.