Java Runnable Interface

Creating Thread using Runnable:

• It is an interface.
• It contains only one specification called run() method.
• We need to override run method to place thread logic.
• The class which is implementing Runnable interface is called Runnable object but not Thread.

interface Runnable
{
	void run();
}

• Thread class is providing constructor to construct the thread from Runnable object.
• We cannot start Runnable object directly.

class Custom implements Runnable
{
	public void run()
	{
		System.out.println("Thread logic...");
	}
}
class CreateThread 
{
	public static void main(String[] args) 
	{
		Custom obj = new Custom();
		obj.start();  -> Error : 
	}
}

• We should create Thread by passing Runnable object as an input to Thread constructor.
• By invoking start() method, we can execute thread logic.

/*
class Thread
{
	Thread(Runnable obj)
	{
		Construct thread from Runnable object
	}
}
*/
class Custom implements Runnable
{
	public void run()
	{
		System.out.println("Thread logic...");
	}
}
class CreateThread 
{
	public static void main(String[] args) 
	{
		Custom obj = new Custom();
		Thread t = new Thread(obj); 
		t.start();
	}
}