Verify there is a combination of unique string

Sree :

class Details{
 String name;
 String age;
 String email;
 String location;
}

1) If there is List of Details as in List<Details> how to verify for a combination of name and email collectively unique. (i.e) For a single email address there cant be two name entry.

2) How to verify the combination of all fields in the class file is unique.

what would be a perfect data structure to address this ?.

OmG :

You can hash values by a separator like #, and then find that all uniques or not. Hash value for a Details is name + "#" + "email in the first case, and is name + "#" + age + "#" + email + "#" + location in the second case. You can using Hashmap to find duplicates if there is any with the specified key (or hash) for each instance of Details.