how to resolve exception while reading private key from file

i am trying to read private key from a file using the below code and getting an exception. is there any way to resolve it? generatePrivate() method throws invalidkeyspecexception.

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;

(...)
try {
             
    Path path = Paths.get(THE_BINARY_ENCODED_FILE_PATH);
    byte[] privKeyByteArray = Files.readAllBytes(path);
    PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privKeyByteArray);
    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
    PrivateKey privateKey= keyFactory.generatePrivate(keySpec);
    
} catch (Exception e) {
    e.printStackTrace();
}

how to solvethis?

My key was invalid. tried with different file and it worked!