Converter.java

/**
 * Created by namchuai on 8/21/17.
 * Use to convert from Unicode code point to UTF-16
 */
public class Converter {
    private static final int BASE_HEX = 0x10000;

    private static int mHexInput = 0x9FFFF;

    public static void main(String[] args) {
        int minusResult = mHexInput - BASE_HEX;

        System.out.println("Minus result: " + Integer.toHexString(minusResult).toUpperCase());

        int charNumOfBinary = 20;

        String binaryString = Integer.toBinaryString(minusResult);

        while (binaryString.length() < charNumOfBinary) {
            binaryString = "0" + binaryString;
        }

        char[] binaryChar = binaryString.toCharArray();

        System.out.print("Minus binary: ");
        for (int i = 0; i < binaryChar.length; i++) {
            if (i != 0 && i % 4 == 0) {
                System.out.print(" ");
            }
            System.out.print(binaryChar[i]);
        }
        System.out.println("");

        final int mid = binaryString.length() / 2;
        String[] parts = {binaryString.substring(0, mid), binaryString.substring(mid)};

        if (parts[0].length() < 10) {
            parts[0] = "00" + parts[0];
        }

        if (parts[1].length() < 10) {
            parts[1] = "00" + parts[1];
        }

        System.out.println(parts[0]);
        System.out.println(parts[1]);

        String highBinary = "110110" + parts[0];
        String lowBinary = "110111" + parts[1];

        System.out.println(highBinary);
        System.out.println(lowBinary);

        int highDecimal = Integer.parseInt(highBinary, 2);
        String highHexStr = Integer.toString(highDecimal, 16).toUpperCase();

        int lowDecimal = Integer.parseInt(lowBinary, 2);
        String lowHexStr = Integer.toString(lowDecimal, 16).toUpperCase();

        System.out.println("High hex: " + highHexStr);
        System.out.println("Low hex: " + lowHexStr);

        System.out.println("Final: \\u" + highHexStr + "\\u" + lowHexStr);
    }
}