It is not encouraged. If you have non JW friends, you keep it to yourself but if someone sees you hanging around with them you WILL get a talking to about bad association.
I have non JW friends. They are better friends then ANY JW friend. They don't dump you when you no longer believe what they believe. Even though you are the same person. They like you for who you are. I had lunch with 2 of them today. No judgement, just a really nice lunch with 2 people who like ME.