How to store and reuse keypair in Java?

I am wanting generate a keypair once and reuse it.

public static KeyPair generateKeyPair() throws Exception {
        KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");
        generator.initialize(2048, new SecureRandom());
        KeyPair pair = generator.generateKeyPair();

        return pair;
}

How do I go about this?