Q.IS IT TRUE IF THE TREE GROWS THORNS THEY ARE DONE ?
I HAVE HAD THE TREES FOR 2 OR 3 YEARS. THEY HAVE THORNS ON THEM. NO FRUIT FOR 1 YEAR.

Certified GKH Gardening Expert
Here's a link for an article that explains why fruit trees grow thorns. I don't believe it means the tree is in trouble. https://www.gardeningknowhow.com/edible/fruits/citrus/thorns-on-citrus-trees.htm
The reasons they have not produced fruit are probably a different issue. I don't know what kind of tree you have, but I hope this article about lemon trees will help with that:
https://www.gardeningknowhow.com/edible/fruits/lemons/lemon-tree-not-fruiting.htm