JAVA THREADS QUIZ

Predict the output:class A implements Runnable{ public void run(){ try{ for(int i=0;i<4;i++){ Thread.sleep(100); System.out.println(Thread.currentThread().getName()); } }catch(InterruptedException e){ } }}public class Test{ public static void main(String argv[]) throws Exception{ A a = new A(); Thread t = new Thread(a, "A"); Thread t1 = new Thread(a, "B"); t.start(); t.join(); t1.start(); }}

None of these

A A A A B B B B

Output order is not guaranteed

A B A B A B A B

Compilation succeed but Runtime Exception

TRUE ANSWER : ?
YOUR ANSWER : ?

What is the output for the below code ?public class Test extends Thread{ public static void main(String argv[]){ Test t = new Test(); t.run(); } public void start(){ for(int i = 0; i < 10; i++){ System.out.println("Value of i = " + i); } }}

A run time error indicating that no run method is defined for the Thread class

A compile time error indicating that no run method is defined for the Thread class

None of these

Clean compile but no output at runtime

Clean compile and at run time the values 0 to 9 are printed out

TRUE ANSWER : ?
YOUR ANSWER : ?

What will be the output?class A extends Thread{ public void run(){ for(int i=0; i<2; i++){ System.out.println(i); } }}public class Test{ public static void main(String argv[]){ Test t = new Test(); t.check(new A(){}); } public void check(A a){ a.start(); }}

Compilation error, class A has no start method

None of these

0 1

Compilation succeed but runtime exception

0 0

TRUE ANSWER : ?
YOUR ANSWER : ?

Predict the output:public class Test extends Thread{ private int i; public void run(){ i++; } public static void main(String[] args){ Test a = new Test(); a.run(); System.out.print(a.i); a.start(); System.out.print(a.i); }}

IllegalThreadStateException is thrown

Prints

Compiler error

TRUE ANSWER : ?
YOUR ANSWER : ?

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

The program compiles fine.

The program will not compile because it does not implement the run() method.

None of these

The program will not compile because it does not contain abstract methods.

TRUE ANSWER : ?
YOUR ANSWER : ?

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 run-test

Compilation fails due to an error on line 4

None of these

Compilation fails due to an error on line 7

run-test

TRUE ANSWER : ?
YOUR ANSWER : ?

What notifyAll() method do?

None of these

Wakes up one threads that are waiting on this object's monitor

Wakes up all threads that are waiting on this object's monitor

Wakes up all threads that are not waiting on this object's monitor

TRUE ANSWER : ?
YOUR ANSWER : ?

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.

None of these

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

TRUE ANSWER : ?
YOUR ANSWER : ?

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

go()

start()

init()

run()

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following are methods of the Thread class?1) yield()2) sleep(long msec)3) go()4) stop()

1 , 2 and 4

3 only

1 and 3

None of these

TRUE ANSWER : ?
YOUR ANSWER : ?