Java provides a powerful mechanism for creating and managing threads, allowing you to write efficient and responsive applications that can handle multiple tasks simultaneously. Multithreading is a feature of Java that allows you to write code that can execute multiple threads of execution in parallel.

Here are some key concepts of multithreading in Java:

1. Thread: A thread is a basic unit of execution in a program. Every Java program has at least one thread, which is called the main thread. You can create additional threads to run different parts of your program concurrently.

2. Runnable: A Runnable is an interface that defines a single method, run(), that can be used to execute a block of code in a new thread. You can create a new thread by passing an instance of a class that implements the Runnable interface to the Thread constructor.

3. Synchronization: Synchronization is the process of controlling access to shared resources in a multithreaded environment. You can use the synchronized keyword to ensure that only one thread at a time can access a shared resource.

4. Thread safe: A thread-safe program is one that can be safely executed by multiple threads at the same time. You can use various techniques such as synchronization and locking to ensure that your program is thread safe.

5. Thread pool: A thread pool is a group of pre-created threads that can be used to execute a large number of small tasks. By reusing threads, you can avoid the overhead of creating and destroying threads for every task.

6. Deadlock: A deadlock occurs when two or more threads are blocked waiting for each other to release a resource. Deadlocks can cause your program to hang or crash, so it's important to avoid them.

Here's an example of how to create a new thread using the Runnable interface:

public class MyRunnable implements Runnable {
    public void run() {
        // code to be executed in the new thread
    }
}

// create a new thread and start it
Thread thread = new Thread(new MyRunnable());
thread.start();

In this example, we define a new class called MyRunnable that implements the Runnable interface. We then create a new thread by passing an instance of MyRunnable to the Thread constructor and call the start() method to start the thread.

Note that when you create a new thread, it will execute independently of the main thread, so you need to use synchronization and other techniques to coordinate the actions of multiple threads if they need to interact with each other or access shared resources.