Thread

[Abhi vijay]

Source: Devaka Cooray's Exam Simulator(made some changes)

 public class TRead extends Thread
{
TRead tr=new TRead();
public synchronized void run(){
System.out.print("1");
System.out.print("2");
}
public Thread getInst(){
return tr;
}
public static void main(String ars[])
{
for(int i=0; i<1; i++){
new TRead().getInst().start();
}
}
} 

here at TRead.<init>(TRead.java:3) is printed many times???

[Devaka Cooray]

 

here at TRead.<init>(TRead.java:3) is printed many times???

What you have seen is a part of the stack trace of StackOverFlowError. Well, you had modified the question, so now this is not a thread problem. This exception (StackOverFlowError) is occured when you are trying to recursively create instances of TRead class.

Try to compile and run the following modified program (this is cleary not about threads na), and try to understand this yourself

class TRead{
TRead tr=new TRead();
public static void main(String ars[]){
new TRead();
}
} 

Devaka.

[Wouter Oet]

Thats because when you create a TRead object, it creates another TRead object and another and another....

I think this is a strange question because there is no need for a instance variable of type TRead because a TRead object is a Thread already. No need for getInst() and the run doesn't need to be synchronized.

Wouter Oet

[Treimin Clark]

Wouter,
It was a modified question.
You should read the answers.

[Devaka Cooray]

 

When i replace TRead tr=new TRead(); with
static TRead tr=new TRead();

The answer is 12..

Yes! If tr is NON-static, there should be a NEW TRead instance associated with each TRead instances; which provides a recursive access.

But if tr is a static variable, a single instance of TRead will be shared within every instances of TRead class. So it doesn't provide a recursive execution.

Devaka.

[Abhi vijay]

Thanks Devaka. I understood.