What will be the output of this program? Java class TestThread extends Thread { public void run() { try { Thread.sleep(1000); System.out.println("Thread Running"); } catch (InterruptedException e) { System.out.println("Interrupted"); } } public static void main(String[] args) { TestThread t = new TestThread(); t.start(); t.interrupt(); } }

Both A and B, depending on timing

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Java Thread Methods and Daemon Threads

Here are 10 essential multiple-choice questions on Java Thread Methods and Daemon Threads, covering key concepts.

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Question 1

Which method is used to set the name of a thread in Java?

setName()
setThreadName()
setThread()
assignName()

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Question 2

What will be the output of the following code?

Java

class MyThread extends Thread {
    public void run() {
        System.out.println(Thread.currentThread().getName());
    }
    
    public static void main(String[] args) {
        MyThread t1 = new MyThread();
        t1.setName("CustomThread");
        t1.start();
    }
}

Thread-0
MyThread
CustomThread
Compilation Error

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Question 3

What is the key difference between start() and run() in Java threads?

start() creates a new thread, but run() executes in the current thread
Both methods create a new thread
run() is an internal method that should not be called
start() directly calls run() without creating a new thread

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Question 4

What will happen if start() is called twice on the same thread?

The thread runs twice
A new thread is created each time
It throws an IllegalThreadStateException
It runs normally without any issues

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Question 5

What is the effect of Thread.sleep(5000) inside a thread?

The thread is terminated
The thread is paused for 5 seconds but remains in the RUNNABLE state
The thread is paused for 5 seconds and enters the TIMED_WAITING state
The thread releases its lock and resumes immediately

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Question 6

What will be the output of this program?

Java

class TestThread extends Thread {
    public void run() {
        try {
            Thread.sleep(1000);
            System.out.println("Thread Running");
        } catch (InterruptedException e) {
            System.out.println("Interrupted");
        }
    }

    public static void main(String[] args) {
        TestThread t = new TestThread();
        t.start();
        t.interrupt();
    }
}

Thread Running
Interrupted
No Output
Both A and B, depending on timing

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Question 7

Which of the following is true about a daemon thread in Java?

A daemon thread runs in the background and stops when all user threads finish execution
A daemon thread continues running even if all user threads finish
A daemon thread must be manually stopped
The JVM waits for daemon threads to finish before terminating

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Question 8

What happens when setDaemon(true) is called after start()?

The thread becomes a daemon thread
Compilation error
Runtime exception (IllegalThreadStateException)
No effect

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Question 9

How can you check if a thread is a daemon thread?

Using isDaemon() method
Using isDaemonThread() method
Using isBackgroundThread() method
Using getThreadType() method

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Question 10

Which of the following correctly creates and starts a daemon thread?

Java

Thread t = new Thread(() -> System.out.println("Daemon Running"));
t.start();
t.setDaemon(true);

Java

Thread t = new Thread(() -> System.out.println("Daemon Running"));
t.setDaemon(true);
t.start();

Java

Thread t = new Thread(() -> System.out.println("Daemon Running"));
t.setDaemon(false);
t.start();

None of the above

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