The two ways of creating Thread

There are two ways to create a new thread of execution. One is to declare a class to be a subclass of

Thread

. This subclass should override the

run

method of class

Thread

. An instance of the subclass can then be allocated and started. For example, a thread that computes primes larger than a stated value could be written as follows:

class PrimeThread extends Thread {
long minPrime;
PrimeThread(long minPrime) {
this.minPrime = minPrime;
}

public void run() {
// compute primes larger than minPrime
. . .
}
}

The following code would then create a thread and start it running:

PrimeThread p = new PrimeThread(143);
p.start();

The other way to create a thread is to declare a class that implements the

Runnable

interface. That class then implements the

run

method. An instance of the class can then be allocated, passed as an argument when creating

Thread

, and started. The same example in this other style looks like the following:

class PrimeRun implements Runnable {
long minPrime;
PrimeRun(long minPrime) {
this.minPrime = minPrime;
}

public void run() {
// compute primes larger than minPrime
. . .
}
}

The following code would then create a thread and start it running:

PrimeRun p = new PrimeRun(143);
new Thread(p).start();

Every thread has a name for identification purposes. More than one thread may have the same name. If a name is not specified when a thread is created, a new name is generated for it.