Threads - Beginning Java 8 Language Features - page 178

■ Inheriting your class from the Thread class may not be possible if your class already inherits from another
class. In that case, you will need to use the second method. You can use the third method from Java 8. Before Java 8,
it was common to use an anonymous class to define a thread object where the anonymous class would either inherit
from the Thread class or implement the Runnable interface.

Tip

Inheriting Your Class from the Thread Class
When you inherit your class from the Thread class, you should override the run() method and provide the code to be
executed by the thread.

public class MyThreadClass extends Thread {
@Override
public void run() {
System.out.println("Hello Java thread!");
}
// More code goes here
}

The steps to create a thread object and start the thread are the same.

MyThreadClass myThread = new MyThreadClass();
myThread.start();

The thread will execute the run() method of the MyThreadClass class.

Implementing the Runnable Interface
You can create a class that implements the java.lang.Runnable interface. Runnable is a functional interface and it is
declared as follows:

@FunctionalInterface
public interface Runnable {
void run();
}

From Java 8, you can use a lambda expression to create an instance of the Runnable interface.

Runnable aRunnableObject = () -> System.out.println("Hello Java thread!");

Create an object of the Thread class using the constructor that accepts a Runnable object.

Thread myThread = new Thread(aRunnableObject);

Start the thread by calling the start() method of the thread object.

myThread.start();

The thread will execute the code contained in the body of the lambda expressions.