Is it possible in Android to use Thread for organizing multithreaded code, and what problems might arise?

Yes, it is possible. Thread is the base class for creating separate execution threads in Java and, accordingly, in Android.

// Example of creating and starting a Thread
Thread myThread = new Thread(new Runnable() {
    @Override
    public void run() {
        // Code to be executed in the new thread
        Log.d("MyThread", "Running in a new thread");
    }
});
myThread.start();

Main issues when using Thread:

• Thread management: Self-managing the lifecycle of threads can be complex, especially with a large number of them.
• Synchronization: Access to shared resources from different threads requires careful synchronization to avoid race conditions and deadlocks.
• UI interaction: You cannot directly update UI elements from a background thread. A mechanism like Handler is needed to pass data to the main thread (UI thread).
• Memory leaks: If a thread continues to run after the Activity or Fragment is destroyed, it can hold references to the context, causing memory leaks.
• Cancellation complexity: Cancelling a running task in a background thread requires explicit cancellation logic and checking the interruption flag within the thread.

Due to these complexities, Android often prefers to use higher-level APIs and frameworks for multithreading, such as AsyncTask (although deprecated and not recommended for new projects), HandlerThread, ThreadPoolExecutor, as well as libraries like RxJava or Kotlin Coroutines.