Questions and answers for exam Preparation

MCQs

Total Questions : 22 | Page 1 of 3 pages

Question 1. In java a thread can be created by ..........

Both of the above
Extending the thread class.
None of these
Implementing Runnable interface.

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Answer: Option A. -> Both of the above

Question 2. Which of the following constructor of class Thread is valid one?

Thread(Runnable threadOb, String threadName)
Thread(Runnable threadOb, int priority)
None of these
Thread(int priority)
Thread(String threadName, int priority)

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Answer: Option A. -> Thread(Runnable threadOb, String threadName)

Question 3. When a class extends the Thread class ,it should override ............ method of Thread class to start that thread.

run()
start()
init()
go()

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Answer: Option A. -> run()

Question 4. What will be the output of the following program code?public class Test implements Runnable{ public static void main(String[] args){ Thread t = new Thread(this); t.start(); } public void run(){ System.out.println("test"); }}

The program compiles and runs fine and displays test on the console.
The program does not compile because this cannot be referenced in a static method.
The program compiles fine, but it does not print anything because t does not invoke the run() method
None of these

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Answer: Option B. -> The program does not compile because this cannot be referenced in a static method.

Question 5. Analyze the following code:public abstract class Test implements Runnable{ public void doSomething() { };}

None of these
The program compiles fine.
The program will not compile because it does not contain abstract methods.
The program will not compile because it does not implement the run() method.

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Answer: Option B. -> The program compiles fine.

Question 6. Analyze the following code:public class Test implements Runnable{ public static void main(String[] args){ Test t = new Test(); t.start(); } public void run() { }}

The program does not compile because the start() method is not defined in the Test class.
The program compiles, but it does not run because the run() method is not implemented.
The program compiles, but it does not run because the start() method is not defined.
The program compiles and runs fine.

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Answer: Option A. -> The program does not compile because the start() method is not defined in the Test class.

Question 7. What will be the output?class One extends Thread{public void run(){for(int i=0; i

0 0
None of these
0 1
Compilation Error

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Answer: Option C. -> 0 1

Question 8. What will happen when you attempt to compile and run the following code?1. public class Test extends Thread{2. public static void main(String argv[]){3. Test t = new Test();4. t.run();5. t.start();6. }7. public void run(){8. System.out.println("run-test");9. }10. }

run-test
None of these
Compilation fails due to an error on line 4
Compilation fails due to an error on line 7
run-test run-test

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Answer: Option E. -> run-test run-test

Question 9. What will happen after compiling and running following code?class A implements Runnable{ public void run(){ System.out.println("run-a"); }}1. public class Test{2. public static void main(String... args){3. A a = new A();4. Thread t = new Thread(a);5. t.start();6. t.start();7. }8. }

Compilation succeed but Runtime Exception
Compilation fails with an error at line 6
run-a run-a
None of these
run-a

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Answer: Option A. -> Compilation succeed but Runtime Exception

Question 10. Analyze the following code:public class Test implements Runnable{ public static void main(String[] args){ Test t = new Test(); } public Test(){ Thread t = new Thread(this); t.start(); } public void run(){ System.out.println("test"); }}

The program compiles and runs and displays test.
The program compiles fine, but it does not run because you cannot use the keyword this in the constructor.
The program compiles and runs and displays nothing.
The program has a compilation error because t is defined in both the main() method and the constructor Test().

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Answer: Option A. -> The program compiles and runs and displays test.