This piece of code compares if the recovered walletAddress from the signedMessage and Signature matches the desired WalletAddress. This way you can check if the ECDSA signature is valid

ECDSASignatureCheck

// This piece of code compares if the recovered walletAddress from the signedMessage and Signature matches the desired WalletAddress.
    // This way you can check if the ECDSA signature is valid
    public boolean isECDSAValidSignature(String walletAddress, String signature, String originalMessage)
            throws SignatureException, UnsupportedEncodingException {
        if (signature.startsWith("0x")) {
            signature = signature.substring(2);
        }

        
        String r = signature.substring(0, 64);
        String s = signature.substring(64, 128);
        String v = signature.substring(128, 130);

        byte[] messageHash = originalMessage.getBytes("UTF-8");
        byte[] messageHashBinary = Hash.sha3(messageHash);


        // Using Sign.signedPrefixedMessageToKey for EIP-712 compliant signatures.
        String pubkey = Sign.signedPrefixedMessageToKey(messageHashBinary,
                        new Sign.SignatureData(
                                hexStringToByteArray(v)[0],
                                hexStringToByteArray(r),
                                hexStringToByteArray(s)))
                .toString(16);


        String recoveredAddress = "0x" + Keys.getAddress(pubkey);

        recoveredAddress = Keys.toChecksumAddress(recoveredAddress);

        if (recoveredAddress.equals(walletAddress)){
            return true;
        }
        
        return false;
    }