import java.io.UnsupportedEncodingException;

public class Test {

	public static void main(String[] args) throws UnsupportedEncodingException {
		byte[] bytes = new byte[]{(byte) 240, (byte) 159, (byte) 146, (byte) 138};
		String str = new String(bytes, "UTF-8");
		System.out.println(str.length());
		for (int i = 0; i < str.length(); i++)
			System.out.println(Integer.toHexString(str.codePointAt(i)));

		System.out.println();

		char[] chars = Character.toChars(0x1f48a);
		System.out.println(chars.length);
		for (int i = 0; i < chars.length; i++)
			System.out.println(Integer.toHexString(chars[i]));
	}
}

/*
Output:
2
1f48a
dc8a

2
d83d
dc8a
*/