Java KeyGen and Cert question

public void generateUserKeystoreAndCert(String alias,String keystore, String password, String certfile)
  {
 
    KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
    ks.load(null,password.toCharArray());
 
 
    KeyPairGenerator kg = KeypairGenerator.getInstance("SHA1withRSA");
    kg.initialize(1024);
    KeyPair keyPair = kg.generateKeyPair();
    PrivateKey privateKey = keyPair.getPrivate();
    PublicKey publicKey = keyPair.getPublic();
 
    ks.setEntry(alias,privateKey,password);
 
    FileOutputStream fos = new FileOutputStream(keystore);
    ks.store(fos,password);
    fos.close();
    System.out.println("One keystore has been created.");
 
//Now to create a cert ....