There don't seem to be any perfect libraries or ways to do this yourself, unless you have to time to send an email to the email address and wait for a response (this might not be an option though). I ended up using a suggestion from here http://blog.logichigh.com/2010/09/02/validating-an-e-mail-address/ and adjusting the code so it would work in Java.
public static boolean isValidEmailAddress(String email) {
boolean stricterFilter = true;
String stricterFilterString = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
String laxString = ".+@.+\\.[A-Za-z]{2}[A-Za-z]*";
String emailRegex = stricterFilter ? stricterFilterString : laxString;
java.util.regex.Pattern p = java.util.regex.Pattern.compile(emailRegex);
java.util.regex.Matcher m = p.matcher(email);
return m.matches();
}