Concurrent Programming with Threads

# Concurrent Programming with Threads

Concurrent programming with threads involves executing multiple sequences of instructions at the same time. This is achieved by threads, the smallest units of execution in a process.

In Java, you can create a thread by extending the `Thread` class or implementing the `Runnable` interface. Here's an example using `Runnable`:

```java
class MyRunnable implements Runnable {
    public void run() {
        // Code to execute in the thread
    }
}

// To start the thread
Thread thread = new Thread(new MyRunnable());
thread.start();
```

In Python, the `threading` module is used for working with threads:

```python
import threading

def function_to_run():
    # Code to execute in the thread

# To start the thread
thread = threading.Thread(target=function_to_run)
thread.start()
```

Threads can run simultaneously, but they also share resources, which can lead to issues known as race conditions.

To prevent race conditions, the concept of locks or synchronization is used. In Java, the `synchronized` keyword achieves this:

```java
synchronized(obj) {
    // Only one thread can execute this at a time
}
```

In Python, you can use the `Lock` class from the `threading` module:

```python
lock = threading.Lock()

# To acquire the lock
lock.acquire()

# Now only one thread can execute the code here

# To release the lock
lock.release()
```

Remember, concurrent programming with threads can greatly improve the performance of your software, but it requires careful design to avoid issues such as race conditions or deadlock.