crypto/src/main/java/org/springframework/security/crypto/codec/Utf8.java
public static byte[] encode(CharSequence string) {
		try {
			ByteBuffer bytes = CHARSET.newEncoder().encode(CharBuffer.wrap(string));
			byte[] bytesCopy = new byte[bytes.limit()];
			System.arraycopy(bytes.array(), 0, bytesCopy, 0, bytes.limit());

			return bytesCopy;
		}
		catch (CharacterCodingException e) {
			throw new IllegalArgumentException("Encoding failed", e);
		}
	}
public static byte[] encode(CharSequence string) {
		try {
			ByteBuffer bytes = CHARSET.newEncoder().encode(CharBuffer.wrap(string));
			byte[] bytesCopy = new byte[bytes.limit()];
			System.arraycopy(bytes.array(), 0, bytesCopy, 0, bytes.limit());

			return bytesCopy;
		}
		catch (CharacterCodingException e) {
			throw new IllegalArgumentException("Encoding failed", e);
		}
	}
Get the bytes of the String in UTF-8 encoded form.