Normally the timezone will be taken from the OS. I typically have my hardware set to UTC/GMT and then the actual system time set to my local timezone, and I do all that using the standard OS timezone configuring utilities (actually I usually set it as part of the OS installation process and never touch it again).
I thing that if you set the environment variable "TZ" to the appropriate value, the JVM running in that particular shell environment will use it without actually having to change the OS timezone setting. There's probably also a JVM "-D=" property you can set, but I've never looked.
Customer surveys are for companies who didn't pay proper attention to begin with.