Java tutorial
//package com.java2s; import java.util.*; public class Main { private static final Map<Character, Character> H2Z = new HashMap<Character, Character>(); public static String toZenkanaCase(String str) { StringBuilder buffer = new StringBuilder(str); for (int i = 0; i < str.length(); i++) { char c = str.charAt(i); if (H2Z.containsKey(c)) { buffer.setCharAt(i, H2Z.get(c)); } } return buffer.toString(); } }