public static Password exportPrivateKey(String storePath,
                                            Password storePassword,
                                            Password keyPassword,
                                            String storeType,
                                            Password pemKeyPassword) throws Exception {
        try (FileInputStream in = new FileInputStream(storePath)) {
            KeyStore ks = KeyStore.getInstance(storeType);
            ks.load(in, storePassword.value().toCharArray());
            String alias = ks.aliases().nextElement();
            return new Password(pem((PrivateKey) ks.getKey(alias, keyPassword.value().toCharArray()), pemKeyPassword));
        }
    }
Creates a keystore with a single key and saves it to a file.

@param filename String file to save
@param password String store password to set on keystore
@param keyPassword String key password to set on key
@param alias String alias to use for the key
@param privateKey Key to save in keystore
@param cert Certificate to use as certificate chain associated to key
@throws GeneralSecurityException for any error with the security APIs
@throws IOException if there is an I/O error saving the file
clients/src/test/java/org/apache/kafka/test/TestSslUtils.java