What
is Thread in Java
Thread in Java is an independent path of execution which is used to run
two task in parallel. When two Threads run in parallel that is called
multi-threading in Java. Java is multi-threaded from start and excellent
support of Thread at language level e.g. java.lang.Thread class, synchronized
keyword, volatile
and final
keyword makes writing concurrent programs easier in Java than any other
programming language e.g. C++. Being multi-threaded is also a reason of Java's
popularity and being number one programming language. On the other hand if your
program divides a task between two threads it also brings lot of programming
challenges and issues related to synchronization,
deadlock,
thread-safety
and race
conditions. In short answer of question What
is Thread in Java can be given like "Thread is a class in Java but
also a way to execute something in parallel independently in Java". Thread
in Java requires a task which is executed by this thread independently and that
task can be either Runnable or Callable which we will see in next section along
with an example of How to use multiple Thread in Java. Difference
between Thread and Runnable in Java is also a popular thread interview
question in Java.
What is Runnable in Java
Thread
Example in Java.
Here is a simple example of Thread in Java. In this Java program we
create two Thread object and pass them two different Runnable instance
which is implemented using Anonymous class in Java. We have also provided name
to each thread as “Thread A” and “Thread B”, name is optional and if you don’t
give name, Java will automatically provide default name for your Thread like “Thread
0” and “Thread 1”. When we start thread using start() method it
calls run() method which has code for printing name of Thread two times for Thread A
and three times for Thread B.
/**
* Java Program to demonstrate how to use Thread in Java with Example
* Here two threads are provided Runnable interface implementation using
* anonymous class and when started they will print Thread's name.
* @author
*/
public class ThraedExample{
public static void main(String args[]){
//two threads in Java which runs in Parallel
Thread threadA = new Thread(new Runnable(){
public void run(){
for(int i =0; i<2; i++){
System.out.println("This is thread : " + Thread.currentThread().getName());
}
}
}, "Thread A");
//Runnable interface is implemented using Anonymous Class
Thread threadB = new Thread(new Runnable(){
public void run(){
for(int i =0; i<3; i++){
System.out.println("This is thread : " + Thread.currentThread().getName());
}
}
}, "Thread B");
//starting both Thread in Java
threadA.start(); //start will call run method in new thread
threadB.start();
}
}
Output
* Java Program to demonstrate how to use Thread in Java with Example
* Here two threads are provided Runnable interface implementation using
* anonymous class and when started they will print Thread's name.
* @author
*/
public class ThraedExample{
public static void main(String args[]){
//two threads in Java which runs in Parallel
Thread threadA = new Thread(new Runnable(){
public void run(){
for(int i =0; i<2; i++){
System.out.println("This is thread : " + Thread.currentThread().getName());
}
}
}, "Thread A");
//Runnable interface is implemented using Anonymous Class
Thread threadB = new Thread(new Runnable(){
public void run(){
for(int i =0; i<3; i++){
System.out.println("This is thread : " + Thread.currentThread().getName());
}
}
}, "Thread B");
//starting both Thread in Java
threadA.start(); //start will call run method in new thread
threadB.start();
}
}
Output
This is thread :
Thread A
This is thread : Thread A
This is thread : Thread B
This is thread : Thread B
This is thread : Thread B
This is thread : Thread A
This is thread : Thread B
This is thread : Thread B
This is thread : Thread B
That’s all on What is Thread in Java, What is Runnable in Java and
How to use Thread in Java with Example. Thread is one of the most important
concept in Java and must for every Java programmer, it also forms basis of a
Java interview. Checkout these 15
Java multi-threading questions and answer to improve your knowledge on Java
Threads.
Other Java tutorials you may like :
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