Java Threads Test(1st)

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

1 Mark(s)

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

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

1 Mark(s)

3 only
1 , 2 and 4
None of the above
1 and 3

What notifyAll() method do?

1 Mark(s)

None of the above
Wakes up all threads that are not waiting on this object's monitor
Wakes up all threads that are waiting on this object's monitor
Wakes up one threads that are waiting on this object's monitor

Which keyword when applied on a method indicates that only one thread should execute the method at a time.

1 Mark(s)

static
native
synchronized
final
volatile

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. }

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. }

1 Mark(s)

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

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

1 Mark(s)

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

What is the output for the below code ?

class A implements Runnable{
      public void run(){
            System.out.println(Thread.currentThread().getName());
      }
}

1. public class Test{		
2.       public static void main(String... args){	
3.             A a = new A();
4.	       Thread t = new Thread(a);
5.	       t.setName("good");
6.	       t.start();
7.       }
8. }

What is the output for the below code ?

class A implements Runnable{
      public void run(){
            System.out.println(Thread.currentThread().getName());
      }
}

1. public class Test{		
2.       public static void main(String... args){	
3.             A a = new A();
4.	       Thread t = new Thread(a);
5.	       t.setName("good");
6.	       t.start();
7.       }
8. }

1 Mark(s)

null
good
Compilation succeed but Runtime Exception
None of these
Compilation fails with an error at line 5

Analyze the following code:

public abstract class Test implements Runnable{
        public void doSomething() { };
}

Analyze the following code:

public abstract class Test implements Runnable{
        public void doSomething() { };
}

1 Mark(s)

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

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. }

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. }

1 Mark(s)

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

What will be output of the following program code?

public class Test implements Runnable{
      public void run(){
            System.out.print("go");
      }
    
      public static void main(String arg[]) {
            Thread t = new Thread(new Test());
            t.run();
            t.run();
            t.start();
      }
}

What will be output of the following program code?

public class Test implements Runnable{
      public void run(){
            System.out.print("go");
      }
    
      public static void main(String arg[]) {
            Thread t = new Thread(new Test());
            t.run();
            t.run();
            t.start();
      }
}

1 Mark(s)

'go' is printed
'gogogo' is printed
Compilation fails.
An exception is thrown at runtime.
'gogo' is printed

What will happen when you attempt to compile and run the following code?

class A implements Runnable{
      public void run(){
            System.out.println("run-A");
      }
}

1. public class Test{
2.       public static void main(String argv[]){
3.             A a = new A();
4.             Thread t = new Thread(a);
5.             System.out.println(t.isAlive());
6.             t.start();
7.             System.out.println(t.isAlive());
8.       }
9. }

What will happen when you attempt to compile and run the following code?

class A implements Runnable{
      public void run(){
            System.out.println("run-A");
      }
}

1. public class Test{
2.       public static void main(String argv[]){
3.             A a = new A();
4.             Thread t = new Thread(a);
5.             System.out.println(t.isAlive());
6.             t.start();
7.             System.out.println(t.isAlive());
8.       }
9. }

1 Mark(s)

Compilation fails due to an error on line 7
false run-A false
false run-A true
None of these
true run-A true

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);
            }
      }
}

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);
            }
      }
}

1 Mark(s)

None of these
Clean compile but no output at runtime
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
Clean compile and at run time the values 0 to 9 are printed out

What will be the output?

class One extends Thread{
	public void run(){
		for(int i=0; i<2; i++){
			System.out.print(i);
		}
	}
}

public class Test{
	public static void main(String args[]){
		Test t = new Test();
		t.call(new One());
	}
	
	public void call(One o){
		o.start();
	}
}

What will be the output?

class One extends Thread{
	public void run(){
		for(int i=0; i<2; i++){
			System.out.print(i);
		}
	}
}

public class Test{
	public static void main(String args[]){
		Test t = new Test();
		t.call(new One());
	}
	
	public void call(One o){
		o.start();
	}
}

1 Mark(s)

Compilation Error
0 1
0 0
None of these

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");
        }
}

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");
        }
}

1 Mark(s)

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

What will be the output after compiling and executing the following code?

public class Test implements Runnable{
      public static void main(String[] args) throws InterruptedException{
            Thread a = new Thread(new Test());
            a.start();
            System.out.print("Begin");
            a.join();
            System.out.print("End");
      }
    
      public void run(){
            System.out.print("Run");
      }
}

What will be the output after compiling and executing the following code?

public class Test implements Runnable{
      public static void main(String[] args) throws InterruptedException{
            Thread a = new Thread(new Test());
            a.start();
            System.out.print("Begin");
            a.join();
            System.out.print("End");
      }
    
      public void run(){
            System.out.print("Run");
      }
}

1 Mark(s)

An exception is thrown at runtime.
BeginEnd is printed.
BeginRunEnd is printed.
Compilation fails.
BeginEndRun is printed.

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();
      }
}

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();
      }
}

1 Mark(s)

None of these
Compilation succeed but runtime exception
Compilation error, class A has no start method
0 1
0 0

Which of the following constructor of class Thread is valid one?

1 Mark(s)

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

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");
        }
}

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");
        }
}

1 Mark(s)

The program compiles and runs and displays nothing.
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 has a compilation error because t is defined in both the main() method and the constructor Test().

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);
      }
}

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);
      }
}

1 Mark(s)

Prints
Prints
Compiler error
Prints
IllegalThreadStateException is thrown

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();
      }
}

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();
      }
}

1 Mark(s)

Compilation succeed but Runtime Exception
Output order is not guaranteed
A A A A B B B B
None of these
A B A B A B A B

Analyze the following code:

public class Test implements Runnable{
        public static void main(String[] args){
                Test t = new Test();
                t.start();
        }

        public void run() { }
}

Analyze the following code:

public class Test implements Runnable{
        public static void main(String[] args){
                Test t = new Test();
                t.start();
        }

        public void run() { }
}

1 Mark(s)

The program compiles and runs and displays nothing.
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 has a compilation error because t is defined in both the main() method and the constructor Test().

Given the code. What will be the result?

public class Test implements Runnable{
      public static void main(String[] args) throws InterruptedException{
            Thread a = new Thread(new Test());
            a.start();
        
            System.out.print("Begin");
            a.join();
            System.out.print("End");
      }
    
      public void run(){
            System.out.print("Run");
      }
}

Given the code. What will be the result?

public class Test implements Runnable{
      public static void main(String[] args) throws InterruptedException{
            Thread a = new Thread(new Test());
            a.start();
        
            System.out.print("Begin");
            a.join();
            System.out.print("End");
      }
    
      public void run(){
            System.out.print("Run");
      }
}

1 Mark(s)

Compilation fails.
'BeginEnd' is printed.
'BeginRunEnd' is printed.
'BeginEndRun' is printed.
An exception is thrown at runtime.

Java Threads Test(1st) : Question 1 of 22