How to use custom secret key instead of generating a new secret key in AES 256 encryption

Question

I am now trying to develop a AES 256 CFB encryption program in Java.

I wish to use my own secret key (Hex). However, it returned that there is something wrong with the key length.

Here is the code

class encryption_different {
private static String SECRET_KEY = "afd7a42b34f4875e05d210ea1252e02d5305becdb752f3553d657bab1236f733";

public static String encrypt(String strToEncrypt) {
    try {

        //IV handling
        byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        IvParameterSpec ivspec = new IvParameterSpec(iv);
        //convert custom key string to Secret key format
        byte[] decodedKey = Base64.getDecoder().decode(SECRET_KEY);
        SecretKey originalKey = new SecretKeySpec(decodedKey, 0, decodedKey.length, "AES");
        Cipher cipher = Cipher.getInstance("AES/CFB/NoPadding");
        cipher.init(Cipher.ENCRYPT_MODE, originalKey, ivspec);
        return Base64.getEncoder()
               .encodeToString(cipher.doFinal(strToEncrypt.getBytes(StandardCharsets.UTF_8)));
    } catch (Exception e) {
        System.out.println("Error while encrypting: " + e.toString());
    }
    return null;
}
public static void main(String[] args){
    encrypt("password1");
}
}

The error message I got:

Error while encrypting: java.security.InvalidKeyException: Invalid AES key length: 48 bytes

And therefore, I would like to know why I am getting this error message and how to fix it.