new String (s.getBytes ("iso-8859-1"), "UTF-8");

new String (s.getBytes (StandardCharsets.ISO_8859_1), StandardCharsets.UTF_8);

request.setCharacterEncoding("UTF-8");

request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");

<form method="post" enctype="multipart/form-data" acceptcharset="UTF-8" >

-Dfile.encoding=UTF-8

multipartResolver(ContentLengthAwareCommonsMultipartResolver) {
    defaultEncoding = 'UTF-8'
}

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />

jdbc:mysql://127.0.0.1/dbname?requireSSL=false&useUnicode=true&characterEncoding=UTF-8

List<FileItem> items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);

for (FileItem item : items) {
    String fieldName = item.getFieldName();

    if (item.isFormField()) {
        String fieldValue = item.getString("UTF-8"); // <-- HERE

package br.com.teste.filter;

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;

@WebFilter(servletNames={"Faces Servlet"})
public class Filter implements javax.servlet.Filter {

    @Override
    public void destroy() {
        // TODO Auto-generated method stub

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        request.setCharacterEncoding("UTF-8");
        chain.doFilter(request, response);
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // TODO Auto-generated method stub
    }

}

<h:form id="frmt" enctype="multipart/form-data;charset=UTF-8" >
         <!-- your code here -->
    </h:form>

<FORM action="http://server.com/cgi/handle"
       enctype="multipart/form-data"
       method="post">
   <P>
   What is your name? <INPUT type="text" name="submit-name"><BR>
   What files are you sending? <INPUT type="file" name="files"><BR>
   <INPUT type="submit" value="Send"> <INPUT type="reset">
 </FORM>