While it is technically correct to use a Thread
where a Runnable
is called for, the semantics of the two objects are
different, and mixing them is a bad practice that will likely lead to headaches in the future.
The crux of the issue is that Thread
is a larger concept than Runnable
. A Runnable
is an object whose
running should be managed. A Thread
expects to manage the running of itself or other Runnables
.
public static void main(String[] args) { Thread r =new Thread() { int p; @Override public void run() { while(true) System.out.println("a"); } }; new Thread(r).start(); // Noncompliant
public static void main(String[] args) { Runnable r =new Runnable() { int p; @Override public void run() { while(true) System.out.println("a"); } }; new Thread(r).start();