private ECPrivateKey readPrivateKey(File file) {
        KeyFactory keyFactory;
        try {
            keyFactory = KeyFactory.getInstance("EC");
        } catch (NoSuchAlgorithmException e) {
            throw new TechnicalException(e);
        }

        try (var keyReader = new FileReader(file, StandardCharsets.UTF_8);
             var pemReader = new PemReader(keyReader)) {
            var pemObject = pemReader.readPemObject();
            var content = pemObject.getContent();
            KeySpec keySpec = new PKCS8EncodedKeySpec(content);
            return (ECPrivateKey) keyFactory.generatePrivate(keySpec);
        } catch (InvalidKeySpecException | IOException e) {
            throw new TechnicalException(e);
        }
    }
Run a manual test for the {@link AppleClient}.

@author Charley Wu
@since 5.0.0
pac4j-oidc/src/test/java/org/pac4j/oidc/run/RunAppleClient.java