Thread: will u tell me why i am getting output "null"

public class thread {
public static void main(String[] args) {

mythreadprog my1 = new mythreadprog("demo");
// mythreadprog my2 = new mythreadprog("demo2");

}
}



class personal_details
{
String name,mname,lname,course;
int roll_no;

void add_details()
{
name= "chirag";
mname="n";
lname="Shah";
roll_no= 136;
course = "Msc";

}
void print_details()
{

System.out.println(name);
System.out.println(mname);
System.out.println(lname);
System.out.println(roll_no);
System.out.println(course);

}
}




class mythreadprog implements Runnable
{
personal_details p1= new personal_details();
String threadname;
Thread t;
mythreadprog (String name)
{
threadname = name;
t= new Thread(this,"Mydemo");
//System.out.println(t);
t.start();

}


public void run()
{

p1.print_details();

}
}

Your datafield in the personal details class where not initialised.
And your program did not call the method you use to initialise the variable. That is the add_detail() method in the personal details class.

That's why u receive a null output. Since there are no object in the your details you asked the program to print.

yes, i got it correctly now.
Thank you.

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