Also wondering - why Java? Simple script task with cmd below should do the requested reg-update:
REG ADD "HKLM\SOFTWARE\Policies\Google\Update" /V AutoUpdateCheckPeriodMinutes /T REG_DWORD /F /D 0
If you already has Java script and don't wish to have two separate runs then you may create job, add existing java script and new reg-update task to that job.
Just remember that on x64 OS Google registry will be under "Wow6432Node".
Thank you,
Alex.