1. Jarvan
Jarvan is one of the best junglers at the moment. He is great for early game ganks and for initiating fights. His ultimate allows you to focus on one enemy while blocking out others. Jarvan is a very mobile champion. His flag and drag allows him to get over walls, which can help him get into and out of fights. He is a very mobile champ and is a great choice if you are looking to get started in the jungle.
When jungling with Jarvan you will want to build mainly tanky to help out your team as much as possible. However, you will want to build at least one damage item, possibly even two (depending on how your team is doing) if you want to stay in control and contribute to kills in the later game. When playing remember if you are going to ult (cataclysm), you want to make sure your team has enough room to get in, otherwise you will just block them out. Your best bet is to use your E, Q combo until you know the enemy doesn’t have an escape from your ultimate.