No, you can not directly call run method to start a thread. You need to call start method to create a new thread.
If you call run method directly , it won’t create a new thread and it will be in same stack as main.
Lets understand with the help of example:
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package org.arpit.java2blog;
class CustomThread extends Thread {
public void run() {
for (int i = 0; i < 5; i++) {
try {
Thread.sleep(300);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Thread is running :"+i);
}
}
}
public class StartThreadAgainMain {
public static void main(String[] args) {
CustomThread ct1 = new CustomThread();
CustomThread ct2 = new CustomThread();
ct1.run();
ct2.run();
}
}
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When you run above program , you will get below output:
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Thread is running :0
Thread is running :1
Thread is running :2
Thread is running :3
Thread is running :4
Thread is running :0
Thread is running :1
Thread is running :2
Thread is running :3
Thread is running :4
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As you can see when we are directly calling run method, it is not creating new threads.
If you use start instead of run in above example:
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package org.arpit.java2blog;
class CustomThread extends Thread {
public void run() {
for (int i = 0; i < 5; i++) {
try {
Thread.sleep(300);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Thread is running :"+i);
}
}
}
public class StartThreadAgainMain {
public static void main(String[] args) {
CustomThread ct1 = new CustomThread();
CustomThread ct2 = new CustomThread();
ct1.start();
ct2.start();
}
}
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When you run above program , you will get below output:
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Thread is running :0
Thread is running :0
Thread is running :1
Thread is running :1
Thread is running :2
Thread is running :2
Thread is running :3
Thread is running :3
Thread is running :4
Thread is running :4
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You can not directly call run method to create a thread, you need to call start method to create a new thread.
