Save pair keys in text plain

SavePrivateKey.java

Base64.Encoder encoder = Base64.getEncoder();
try (FileWriter out = new FileWriter(fileName)) {
    out.write("----BEGIN RSA PRIVATE KEY----");
    out.write("\n");

    out.write(encoder.encodeToString(prviateKey.getEncoded()));
    out.write("\n");

    out.write("----END RSA PRIVATE KEY----");
    out.write("\n");
} catch (IOException ex) {
    LOG.log(Level.SEVERE, ex.getMessage(), ex);
}

SavePublicKey.java

Base64.Encoder encoder = Base64.getEncoder();
try (FileWriter out = new FileWriter(fileName)) {
    out.write("----BEGIN RSA PUBLIC KEY----");
    out.write("\n");

    out.write(encoder.encodeToString(publicKey.getEncoded()));
    out.write("\n");

    out.write("----END RSA PUBLIC KEY----");
    out.write("\n");
} catch (IOException ex) {
    LOG.log(Level.SEVERE, ex.getMessage(), ex);
}