How does a thread gain control over an object and how is it captured in a multithreaded environment?

In a multithreaded environment, a thread gains control over an object through synchronization mechanisms that provide exclusive access to the resource. In Android (and Java in general), keywords and classes such as synchronized, ReentrantLock, and others are used for this purpose.

When a thread wants to access an object, it attempts to acquire the monitor (lock) of that object. If the monitor is free, the thread gains control and can perform operations on the object. If the monitor is occupied by another thread, the current thread is blocked and waits for it to be released.

Example using synchronized:

public class Counter {
    private int count = 0;

    public synchronized void increment() {
        count++;
    }

    public synchronized int getCount() {
        return count;
    }
}

Here, the increment and getCount methods are synchronized, which guarantees that only one thread at a time can execute these methods, preventing race conditions.

Thus, acquiring an object means obtaining a monitor lock on the object, which ensures thread-safe access to its state.