SHA-256 with salt for hashing produces different values for signature in java - sha256

Question

We have to build a signature string hashed using SHA-256 with random salt and using 10000 iterations. However, when I run the below code with salt, output hash value is not matching at all for the same input string. If I run the code without the salt, hashed value matches. Can someone point out the right way to add a random salt to the SHA-256 digest and get the firstValue/secondValue same below.
import java.security.MessageDigest;
import java.security.SecureRandom;
import org.springframework.security.crypto.codec.Hex;
public class someTester{
public static void main(String[] args) {
String signatureInput = "someStringWhichisSensitive";
String firstSignValue = getSignature(signatureInput);
String secondSignValue = getSignature(signatureInput);
System.out.println("firstSignValue="+firstSignValue);
System.out.println("secondSignValue="+secondSignValue);
}
private static String getSignature(String signatureInput){
MessageDigest md;
String signatureValue = null;
try {
// Create a random salt
SecureRandom sr = new SecureRandom();
byte[] bSalt = new byte[8];
sr.nextBytes(bSalt);
md = MessageDigest.getInstance("SHA-256");
// digest.update(bSalt);
byte[] bDigest = md.digest(signatureInput.getBytes());
// Iterate through 10000 times
for (int i = 0; i < 10000; i++) {
bDigest = md.digest(bDigest);
}
signatureValue = new String(Hex.encode(bDigest));
} catch (Exception e) {
System.out.println("Exception while calculating SHA-256 digest value"+e);
}
return signatureValue;
}
}