Thursday Code Puzzler: Some String Manipulation

private static String getUniqueString(String str1, String str2) {

		/**
		 * Approach : Check all the char of str2 for existence in str1 and if
		 * NOT exists then print.
		 */
		long startTime = Calendar.getInstance().getTimeInMillis();

		HashSet<Character> alreadyProcessed = new HashSet<Character>();

		for (int i = 0; i < str2.length(); i++) {

			/**
			 * Removing extra cycle for repetitive Char
			 */
			if (alreadyProcessed.contains(str2.charAt(i)))
				break;

			boolean charExists = false;
			for (int j = 0; j < str1.length(); j++) {
				if (str2.charAt(i) == str1.charAt(j)) {
					charExists = true;

					/**
					 * Require to reduce extra cycle for repetitive Char.
					 */
					alreadyProcessed.add(str2.charAt(i));

					/**
					 * We are using break hear because it will reduce
					 * unnecessary time for repetitive char.
					 */
					break;
				}
			}

			if (!charExists)
				System.out.print(str2.charAt(i));
		}
		long endTime = Calendar.getInstance().getTimeInMillis();
		System.out.println("\nStart Time: " + startTime + " - End Time: " + endTime);
		System.out.println("Approach Total Time(mills) : " + (endTime - startTime));

		/**
		 * Approach Ends
		 */

		return null;
	}

    // Well, it's a solution!! :)

    String removeChars(final String input, final String removed) {
        byte[] charTable = new byte[8192];
        for(int i = 0 ; i < removed.length() ; i++) {
            char ch = removed.charAt(i);
            charTable[ch / 8] |= (1 << (ch & 7));
        }
        StringBuilder sb = new StringBuilder(input.length());
        for(int i = 0 ; i < input.length() ; i++ ) {
            char ch = input.charAt(i);
            if((charTable[ch / 8] & (1 << (ch & 7))) == 0) {
                sb.append(ch);
            }
        }
        return sb.toString();
    }

 public static String removeChars(String string, String removeString) {
        char[] removeChars = removeString.toCharArray();
        Arrays.sort(removeChars);
        char[] array = string.toCharArray();
        CharBuffer buffer = CharBuffer.allocate(array.length);
        for (char c : array) {
            if (Arrays.binarySearch(removeChars, c) < 0) {
                buffer.append(c);
            }
        }
        return buffer.flip().toString();
    }