What tools and mechanisms do you use to implement and manage multithreading in applications?

In Android, data transfer between screens (Activity, Fragment) is done using:

• Intent with Extras — the most common way to pass data between Activities. You can put primitive types, Serializable, Parcelable objects.

Intent intent = new Intent(CurrentActivity.this, NextActivity.class);
intent.putExtra("key", "value");
startActivity(intent);

• Bundle — used for passing data between Fragments or saving state.

• ViewModel and SharedViewModel — for data exchange between fragments within the same Activity via shared ViewModel.

• Singleton or global classes — for storing data accessible from different parts of the app (not recommended due to state management issues).

• Architecture components (LiveData, StateFlow) — for reactive data exchange.

• Third-party libraries (EventBus, RxJava) — for event and data passing between components.

The choice depends on the app architecture and data volume.