What is Main thread?
In Java, when a program starts
executing, a thread begins running immediately. This thread is called main
thread of that program. When any program starts executing in Java then the main
thread is the first thread that starts running and also, often it is the last
thread to finish its execution.
Why main thread is required?
1. From the main thread other child
threads are produced.
2. Main thread is responsible for
various shutdown activities of any program in Java. So it is often the last
thread to finish its execution.
From the above
discussion it is clear that, the main threads are created automatically when
any program starts up in Java. In some situations it may be necessary for you
to control the main thread. You can do this by obtaining a reference to it by
calling currentThread() method which
is a public static member of Thread class.
The below example program shows how the
main thread is controlled like any other thread in Java by getting a reference
to it.
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package blog.exception.mainThread;
public class DemoMainThread
{
public static void main(String[] args)
{
Thread th=Thread.currentThread();
System.out.println("the Main thread i.e
current thread "+th);
System.out.println();
//get current thread
name using getName()
System.out.println("current thread name
before renaming is= "+th.getName());
System.out.println();
//rename the current
thread using setName()
th.setName("Demo
Thread");
System.out.println("current thread name
after renaming is="+th.getName());
}
}
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Output:
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the Main thread i.e current thread Thread[main,5,main]
current thread name before renaming is= main
current thread name after renaming is=Demo Thread
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In above program you can see a reference is
obtained to the main thread by using currentThread()
method defined by the Thread class.
The name of the main thread is displayed by using getName() method and using setName()
method the name main is changed to Demo
Thread. Again after renaming, the new thread name is displayed by using setName() method.
Note: All the currentThread(), getName() and setName()
methods used in the above example are defined by the Thread class.
