FAQ for Java SDK

Why are there two subscribe methods?

The Java SDK supports a modern, entity-based flow and retains a legacy subscribe() for backward compatibility.

Use the modern flow documented in Subscribe. It creates a Subscription or a SubscriptionSet, uses an event listener, and can resume from a timetoken with SubscriptionCursor. The legacy builder pubnub.subscribe() is documented in Subscribe (old) and remains for existing applications.

Why does encryption use AES-128 when cryptoModule is configured?

If a call supplies a customCipherKey (for encrypt/decrypt) or a cipherKey for stream helpers, that argument overrides the configured cryptoModule for that operation and uses legacy Advanced Encryption Standard (AES) with 128-bit keys. Remove those arguments to use the cryptoModule configuration (AES‑256‑CBC), or configure a separate cryptoModule instance for partial encryption scenarios.

For details, refer to CryptoModule configuration.