What happens if start() is called twice on the same thread? Java class MyThread extends Thread { public void run() { System.out.println("Running..."); } public static void main(String[] args) { MyThread t = new MyThread(); t.start(); t.start(); } }

Throws IllegalThreadStateException

Java Thread Basics and Lifecycle

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Question 1

Which of the following is the correct way to create a thread in Java?

A
Extending the Thread class
B
Implementing the Runnable interface
C
Both A and B
D
Using the Callable interface only

Question 2

What will be the output of the following code?

Java

class MyThread extends Thread {
    public void run() {
        System.out.println("Thread is running");
    }

    public static void main(String[] args) {
        MyThread t = new MyThread();
        t.run();
    }
}

A
Thread is running
B
Compilation Error
C
No Output
D
Runtime Exception

Question 3

Which method is used to start a thread in Java?

A
run()
B
start()
C
execute()
D
begin()

Question 4

What is the initial state of a thread when it is created but not yet started?

A
NEW
B
RUNNABLE
C
BLOCKED
D
WAITING

Question 5

Which of the following statements about the Runnable interface is true?

A
It contains the start() method
B
It contains the run() method
C
It can only be implemented by a class that extends Thread
D
It cannot be used for multithreading

Question 6

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

Java

class MyThread extends Thread {
    public void run() {
        System.out.println("Running...");
    }
    
    public static void main(String[] args) {
        MyThread t = new MyThread();
        t.start();
        t.start();
    }
}

A
Thread runs twice
B
Compiles and runs normally
C
Throws IllegalThreadStateException
D
No output

Question 7

Which of the following is NOT a valid thread state in Java?

A
NEW
B
TERMINATED
C
RUNNING
D
TIMED_WAITING

Question 8

What happens if sleep(1000) is called inside a thread?

A
Thread execution is paused for 1 second
B
Thread is terminated
C
Thread goes to NEW state
D
Thread execution continues immediately

Question 9

What will be the output of the following code?

Java

class Geeks {
    public static void main(String[] args) {
        Thread t = new Thread(() -> System.out.println("Hello from Thread"));
        t.start();
    }
}

A
Hello from Thread
B
Compilation Error
C
No Output
D
Runtime Exception

Question 10

Which method is used to wait for a thread to finish execution?

A
wait()
B
sleep()
C
join()
D
yield()

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