To answer this question, let's go through each option to understand why it is correct or incorrect:

Option A) Compile time error, class Rpcraven does not import java.lang.Thread - This option is incorrect. The java.lang.Thread class is part of the Java standard library and does not require an explicit import statement.

Option B) Output of One One Two Two - This option is correct. The main method creates two instances of the Pmcraven class, passing "one" and "two" as arguments to the constructor. Each instance of Pmcraven is a separate thread. When the run method is called on each thread, it prints the value of sTname twice, resulting in the output "One One Two Two".

Option C) Output of One Two One Two - This option is incorrect. The run method of Pmcraven does not alternate the printing of "One" and "Two". Instead, it prints the value of sTname twice in a row before moving on to the next thread.

Option D) Output of One Two Two One - This option is incorrect. The run method of Pmcraven does not print "Two" before printing "One" for the second time. Instead, it prints the value of sTname twice in a row before moving on to the next thread.

The correct answer is B. This option is correct because the output of the code will be "One One Two Two" as explained above.

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• Wrong explanation

To answer this question, let's analyze the given code:

public class Rpcraven {
    public static void main(String argv[]){
        Pmcraven pm1 = new Pmcraven("one");
        pm1.run();
        Pmcraven pm2 = new Pmcraven("two");
        pm2.run();
    }
}

class Pmcraven extends Thread {
    private String sTname="";

    Pmcraven(String s) {
        sTname = s;
    }

    public void run(){
        for(int i =0; i < 2 ; i++){
            try {
                sleep(1000);
            } catch(InterruptedException e){ }
            yield();
            System.out.println(sTname);
        }
    }
}

The code defines a class Rpcraven with a main method, and a class Pmcraven that extends Thread.

In the main method, two Pmcraven objects pm1 and pm2 are created with arguments "one" and "two" respectively. The run method of each object is then called.

In the Pmcraven class, the run method contains a loop that runs twice. Inside the loop, the thread sleeps for 1 second, yields the CPU, and then prints the value of sTname.

Now, let's go through each option to determine which statement is true:

Option A) Compile time error, class Rpcraven does not import java.lang.Thread - This option is incorrect. The java.lang.Thread class is automatically imported by default in Java, so there is no need for an explicit import statement.

Option B) Output of One One Two Two - This option is correct. The program creates two Pmcraven threads, pm1 and pm2, with arguments "one" and "two" respectively. When the run method of each thread is called, it enters a loop that runs twice. In each iteration, it sleeps for 1 second, yields the CPU, and then prints the value of sTname. Therefore, the output will be "One One Two Two".

Option C) Output of One Two One Two - This option is incorrect. The run method of pm1 is called before the run method of pm2, so it will complete its execution first. Therefore, the output will start with "One" twice, followed by "Two" twice.

Option D) Output of One Two Two One - This option is incorrect. The run method of pm1 is called before the run method of pm2, so it will complete its execution first. Therefore, the output will start with "One" twice, followed by "Two" twice.

The correct answer is option B) Output of One One Two Two.

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• Wrong explanation

To answer this question, let's analyze the given code:

public class Bground extends Thread{
    public static void main(String argv[]){
        Bground b = new Bground();
        b.run();
    }

    public void start(){
        for (int i = 0; i < 10; i++){
            System.out.println("Value of i = " + i);
        }
    }
}

In this code, the class Bground extends the Thread class. The Thread class provides a run method that is executed when a thread is started.

However, in this code, the start method is overridden in the Bground class. This start method contains a loop that prints the values of i from 0 to 9.

Now, let's analyze the main method. It creates an instance of the Bground class and calls the run method on it.

The issue with this code is that it directly calls the run method instead of using the start method, which is the correct way to start a thread. When the run method is called directly, it runs in the same thread as the caller. This means that the loop in the start method will execute sequentially without creating a new thread.

Therefore, when you attempt to compile and run this code, it will compile without any errors (hence "Clean compile"), but there will be no output at runtime (hence "no output at runtime"). The correct answer is option D.

If you want the code to create a new thread and execute the loop concurrently, you should change b.run() to b.start(). This will start a new thread that executes the run method, and you will see the values of i printed out.

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• Wrong explanation