Here you can find the source of asciiToUnicode(String theString)
public static String asciiToUnicode(String theString) throws IllegalArgumentException
//package com.java2s; public class Main { public static String asciiToUnicode(String theString) throws IllegalArgumentException { char aChar; int len = theString.length(); StringBuffer outBuffer = new StringBuffer(len); for (int x = 0; x < len;) { aChar = theString.charAt(x++); if (aChar == '\\') { aChar = theString.charAt(x++); if (aChar == 'u') { // Read the xxxx int value = 0; for (int i = 0; i < 4; i++) { aChar = theString.charAt(x++); switch (aChar) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': value = (value << 4) + aChar - '0'; break; case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': value = (value << 4) + 10 + aChar - 'a'; break; case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': value = (value << 4) + 10 + aChar - 'A'; break; default: throw new IllegalArgumentException("Malformed \\uxxxx encoding."); }//from w w w . ja v a 2 s .c o m } outBuffer.append((char) value); } else { if (aChar == 't') aChar = '\t'; else if (aChar == 'r') aChar = '\r'; else if (aChar == 'n') aChar = '\n'; else if (aChar == 'f') aChar = '\f'; outBuffer.append(aChar); } } else { outBuffer.append(aChar); } } return outBuffer.toString(); } }