Utilitário para substituição de acentos de uma string

StringUtil.java

package com.github.nidorx;

import java.util.Map;
import java.util.HashMap;

public final class StringUtil {
    
    private static final Map<String, String> DIACRITCS = new HashMap<>();

    static {
        DIACRITCS.put("á", "a");
        DIACRITCS.put("à", "a");
        DIACRITCS.put("ã", "a");
        DIACRITCS.put("â", "a");
        DIACRITCS.put("ä", "a");
        DIACRITCS.put("Á", "A");
        DIACRITCS.put("À", "A");
        DIACRITCS.put("Ã", "A");
        DIACRITCS.put("Â", "A");
        DIACRITCS.put("Ä", "A");
        DIACRITCS.put("é", "e");
        DIACRITCS.put("è", "e");
        DIACRITCS.put("ê", "e");
        DIACRITCS.put("ë", "e");
        DIACRITCS.put("É", "E");
        DIACRITCS.put("È", "E");
        DIACRITCS.put("Ê", "E");
        DIACRITCS.put("Ë", "E");
        DIACRITCS.put("í", "i");
        DIACRITCS.put("ì", "i");
        DIACRITCS.put("î", "i");
        DIACRITCS.put("ï", "i");
        DIACRITCS.put("Í", "I");
        DIACRITCS.put("Ì", "I");
        DIACRITCS.put("Î", "I");
        DIACRITCS.put("Ï", "I");
        DIACRITCS.put("ó", "o");
        DIACRITCS.put("ò", "o");
        DIACRITCS.put("õ", "o");
        DIACRITCS.put("ô", "o");
        DIACRITCS.put("ö", "o");
        DIACRITCS.put("Ó", "O");
        DIACRITCS.put("Ò", "O");
        DIACRITCS.put("Õ", "O");
        DIACRITCS.put("Ô", "O");
        DIACRITCS.put("Ö", "O");
        DIACRITCS.put("ú", "u");
        DIACRITCS.put("ù", "u");
        DIACRITCS.put("û", "u");
        DIACRITCS.put("ü", "u");
        DIACRITCS.put("Ú", "U");
        DIACRITCS.put("Ù", "U");
        DIACRITCS.put("Û", "U");
        DIACRITCS.put("Ü", "U");
        DIACRITCS.put("ñ", "n");
        DIACRITCS.put("Ñ", "N");
        DIACRITCS.put("ç", "c");
        DIACRITCS.put("Ç", "C");
        DIACRITCS.put("ÿ", "y");
        DIACRITCS.put("ý", "y");
        DIACRITCS.put("Ý", "Y");
    }
    
    /**
     * Faz a substituição de acentos e caracteres especiais
     *
     * @param exp {@literal @todo Documentar parâmetro}
     * @return {@literal @todo Documentar retorno}
     */
    public static String unaccent(final String exp) {
        String out = exp;
        for (Map.Entry<String, String> entry : DIACRITCS.entrySet()) {
            String key = entry.getKey();
            String value = entry.getValue();
            out = out.replaceAll(key, value);
        }
        return out;
    }
}