Converting a private key in PEM format

I created a self signed certificate with Java code and added it to KeyStore. Now I want to export the private key and generated certificate to a PEM file. Is it possible to achieve this without any third party library? Below is the code I am using to generate a self-service certificate.

  public void createSelfSignedSSLCertificate() {
    try {            
        final CertAndKeyGen keypair = new CertAndKeyGen("RSA", "SHA1WithRSA", null);
        final X500Name x500Name =
            new X500Name(commonName, organizationalUnit, organization, city, state, country);
        keypair.generate(keysize);
        final PrivateKey privKey = keypair.getPrivateKey();
        final X509Certificate[] chain = new X509Certificate[1];
        chain[0] = keypair.getSelfCertificate(x500Name, new Date(), validity * 24 * 60 * 60);
        final String alias = JettySSLConfiguration.SSL_CERTIFICATE_ALIAS;
        keyStore.setKeyEntry(alias, privKey, keyStorePassword.toCharArray(), chain);
    } catch (final Exception e) {
       // Handle Exception
    }       
}

      

        
        
        
      

    

Any suggestion on how to export the key and certificate to a PEM file would be really helpful.