I'm using EC2 of Amazon to host a website built in JSP :
http://ec2-50-17-144-64.compute-1.amazonaws.com:8080/p2p
And I bought this domain: www.p2pbrasil.com
How can I redirect www.p2pbrasil.com to my website in Amazon EC2 ?
When someone type www.p2pbrasil.com it redirects to http://ec2-50-17-144-64.compute-1.amazonaws.com:8080/p2p ?
You need to do two things
If they do not allow you to set the A record directly, find a DNS management service like ZoneEdit, register your domain as a zone there and ZoneEdit will give you the nameservers to enter in the admin panel of your domain provider. You can then add the A record for the domain in ZoneEdit.
I only mention ZoneEdit because the basic service is free, you could also use Amazon route 53 or a similar pay-for service, if you preferred.