This is a great question, perhaps my Number One pet peeve are jumping dogs generally but especially larger ones, like V's.
It's just best to avoid problems than fix them, so generally from puppyhood bend down to greet your pup and praise for not jumping (and alternately, a stern
"No jump", no squirt bottle necessary) usually works. Likewise, turning quickly when they attempt to jump works well, too. In your case, at 15 months, he's unfortunately learned a bad behavior and it's now remedial. So, snap a leash on him to keep him down, praise consistently with "Good down", and he should get it after a while.