import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.math.BigInteger;

public class CharAusUnicode {

	public static void main(String[] args) {

		System.out.println("Entity-String: \u00FC"); // ü

		System.out.println("String aus CharArray: " + stringFromCharArray()); // \u00FC

		System.out
				.println("Entity-String aus Datei: " + stringFromFileString()); // \u00FC

		System.out.println("Konvertierter Entity-String aus Datei: "
				+ convertUnicode(stringFromFileString())); // ü
	}

	private static String stringFromFileString() {
		String s = "", str = "";
		BufferedReader buff = null;
		try {
			buff = new BufferedReader(new FileReader(new File(
					"test.txt")));
			while ((s = buff.readLine()) != null) {
				str += s;
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return str;
	}

	private static String stringFromCharArray() {
		char[] c = { '\\', 'u', '0', '0', 'F', 'C' };
		return new String(c);
	}

	private static String convertUnicode(String s) {
		if (s.startsWith("\\u")) {
			String numberStr = s.substring(2);
			char c = (char) new BigInteger(numberStr, 16).intValue();
			return new Character(c).toString();
		}
		return s;
	}
}