Taking the content from my previous answer here, you can use java.text.Normalizer
which comes close to normalizing Strings in Java. An example of normalization would be;
Accent removal:
String accented = "árvíztűrő tükörfúrógép";
String normalized = Normalizer.normalize(accented, Normalizer.Form.NFD);
normalized = normalized.replaceAll("[^\\p{ASCII}]", "");
System.out.println(normalized);
Gives;
arvizturo tukorfurogep