In Jainism, dairy products are generally considered acceptable for many lay Jains who follow ahimsa (non-violence), so ice cream made from dairy is usually allowed for those who eat dairy. However, there are variations:

• Some Jains, especially among those who practice stricter ahimsa or who follow vegan norms, may avoid dairy entirely.
• There are also individuals who fast or restrict certain foods during specific observances, which could include dairy at times.

So, whether ice cream is okay depends on your personal or community practice (Digambar vs. Shwetambar traditions, and your own vows about dairy). If you want, I can explain how these views differ between Digambar and Shwetambar traditions in more detail.