How to implement multithreading in a program?

To implement multithreading in an Android application, several approaches can be used:

1. Thread Class — create a new thread by overriding the run() method:

new Thread(new Runnable() {
    @Override
    public void run() {
        // code to execute in a separate thread
    }
}).start();

2. Using Handler and Looper — for message exchange between threads.

3. AsyncTask (deprecated but still common) — simplifies executing background tasks with UI updates.

4. ExecutorService — a thread pool for managing multiple tasks.

5. Kotlin Coroutines — a modern and convenient way of asynchronous programming, allowing writing code similar to synchronous code.

Example of creating and starting a thread:

Thread thread = new Thread(new Runnable() {
    @Override
    public void run() {
        // Long-running operation
    }
});
thread.start();

It is important to remember that UI updates should only occur on the main thread (UI thread), so mechanisms like Handler, runOnUiThread(), or others are used to pass results from background threads.