THREAD & CONCURRENCY

Question 1:What is the output for the below code ?
public class B extends Thread{
public static void main(String argv[]){
B b = new B();
b.run();
}
public void start(){
for (int i = 0; i < 10; i++){
System.out.println("Value of i = " + i);
} 
}
}

A)A compile time error indicating that no run method is defined for the Thread class
B)A run time error indicating that no run method is defined for the Thread class
C)Clean compile and at run time the values 0 to 9 are printed out
D)Clean compile but no output at runtime
 answer 1: D
 This is a bit of a sneaky one as I have swapped around the names of the methods you need to define and call when running .

Question no -2 What is the output for the below code ?

public class Test extends Thread
{
    static String sName = "good";
    public static void main(String argv[]){
     Test t = new Test();
    t.nameTest(sName);
    System.out.println(sName);
   
    }
    public void nameTest(String sName){
            sName = sName + " idea ";
             start();
    }
    public void run(){
   
    for(int i=0;i  <  4; i++){
            sName = sName + " " + i;
           
    }
    }

}

A)good
B)good idea
C)good idea good idea
D)good 0 good 0 1

Answer 2: A
Change value in local methods wouldn’t change in global in case of String ( because String object is immutable).

Question no -3 What is the output for the below code ?

public class Test{
 public static void main(String argv[]){
 Test1 pm1 = new Test1("One");
 pm1.run();
 Test1 pm2 = new Test1("Two");
 pm2.run();

 }
}

class Test1 extends Thread{
private String sTname="";
Test1(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);
  }

 }
}

A)Compile error
B)One One Two Two
C)One Two One Two
D)One Two

Answer 3: B
If you call the run method directly it just acts as any other method and does not return to the calling code until it has finished executing
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