Getting & Setting Name of Thread MCQ

Java Multithreading MCQ Part-3 | Getting & Setting Name of Thread MCQ | Also see:- Define Thread in Java Multithreading Interview Questions

Q1) How can we get an instance of the current thread?

a) currentThread()
b) Thread.currentThread()
c) getInstance()
d) Thread.getInstance()

View Answer Answer:- b) Thread.currentThread()

In the Thread class, currentThread() method is a static method which returns an instance of current Thread.

Q2) Which method is used to get the name of a thread?

a) getName()
b) getThreadName()
c) name()
d) None of these

View Answer Answer:- a) getName()

Q3) Which method is used to set the name of a thread?

a) setName()
b) setThreadName()
c) name()
d) None of these

View Answer Answer:- a) setName()

Q4) Find the output of the below program?

public class Test {
   public static void main(String[] args) {
      System.out.println(Thread.currentThread().getName());
   }
}

a) Main
b) main
c) Main thread
d) main thread

View Answer Answer:- b) main

The main() method is executed by the “main” thread.

Q5) Find the output of the below program?

public class Test {
   public static void main(String[] args) {
      Thread.currentThread().setName("KnowProgram");
      System.out.println(Thread.currentThread().getName());
   }
}

a) main
b) KnowProgram
c) Compile time error
d) Exception

View Answer Answer:- b) KnowProgram

Q6) Find the output of the below program?

class MyThread extends Thread { }
public class Test {
   public static void main(String[] args) {
      MyThread mt = new MyThread();
      mt.start();
      System.out.println(mt.getName());
   }
}

a) thread-1
b) thread-0
c) thread-N
d) main

View Answer Answer:- b) thread-0

By default JVM gives the name of the thread as thread-0. The next thread name will be thread-1, thread-2, and so on.

Q7) Find the output of the below program?

class MyThread extends Thread { }
public class Test {
   public static void main(String[] args) {
      MyThread mt = new MyThread();
      mt.start();
      System.out.println(Thread.currentThread().getName());
   }
}

a) thread-1
b) thread-0
c) thread-N
d) main

View Answer Answer:- d) main

The getName() method is called on the current thread object not on the “mt” object.

Q8) What will be the output of the below program?

class MyThread extends Thread {
   public void run() {
      System.out.print(Thread.currentThread().getName()+" ");
      System.out.print(this.getName());  
   }
}

public class Test {
   public static void main(String[] args) {
      MyThread mt = new MyThread();
      mt.start();
   }
}

a) thread-0 main
b) thread-0 thread-0
c) Compile time error
d) Run-time Exception

View Answer Answer:- b) thread-0 thread-0

Both Thread.currentThread().getName() & this.getName() give the same result.

Q9) What is the possible output of the below program?

class MyThread extends Thread {
   public void run() {
      System.out.println(Thread.currentThread().getName());
   }
}

public class Test {
   public static void main(String[] args) {
      MyThread mt = new MyThread();
      mt.start();
      int count = 0;
      for (int i=0; i<8000; i++) {
         count++;         
      }
      mt.setName("Child-thread");
   }
}

a) thread-0
b) Child-thread
c) Sometimes (a) or Sometimes (b)
d) Error or Exception

View Answer Answer:- c) Sometimes (a) or Sometimes (b)

Q10) Find the output of the below program?

class MyThread extends Thread {
   public void run() {
      try {
         sleep(2000);
      } catch(Exception e) { }
      System.out.println(Thread.currentThread().getName());
   }
}

public class Test {
   public static void main(String[] args) {
      MyThread mt = new MyThread();
      mt.start();
      mt.setName("Child-thread");
   }
}

a) thread-0
b) Child-thread
c) Sometimes (a) or Sometimes (b)
d) Error or Exception

View Answer Answer:- b) Child-thread

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