StackOverflowError

[Janki Shah]

public class Test1  
{
    Test1 test = new Test1(); // how this line creates StackOverflowError?
    String x="a";
    public Test1()
    {
        x = "b";
    }
    public static void main(String[] args) 
    {
           System.out.println(new Test1().x);  
    }
}

abstract class Abs 
{
    static
    {
        System.out.print("T");
    }
    public Abs()
    {
        System.out.print("W");
    }
}

[Seetharaman Venkatasamy]

Test1 test = new Test1(); // how this line creates StackOverflowError?
    String x="a";
    public Test1()
    {
        x = "b";
    }

is same as

Test1 test = null;
    String x=null;
    public Test1()
    {
        test = new Test1();//recursive call with out base condition
        x="a";
        x = "b";
    }

so, every recursive call a stack object created by jvm endlessly, hence that error.

[Matthew Brown]

Or to put it another way: every time you create a Test1, that creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1, which creates a new Test1...

[Seetharaman Venkatasamy]

Matthew Brown wrote:which creates a new Test1...

Yes, at last no instances are created *fully*/consistenly

[Janki Shah]

Thank you Seetharaman and Matthew. So, in this case #2 will cause a Test1 class to load and while loading it will create another class instance at #1 and while loading that instance it will load another class instance at #1 and so on... Is this where the recursion happening?

public class Test1  
{
    Test1 test = new Test1(); // [# 1]this will call #2
    String x="a";
    public Test1()
    {
        x = "b";
    }
    public static void main(String[] args) 
    {
           System.out.println(new Test1().x);  // [# 2] this will call #1
    }
}

[Seetharaman Venkatasamy]

when you say java x.y.z.ClasstoRun then Jvm load that class and search for a main method...and then creating instance etc.. got the difference?

[Janki Shah]

So, in this case, when jvm load the class what line will be executed first #1 or #2 (from main method)?

public class Test1  
{
    Test1 test = new Test1(); //#1
    String x="a";
    public Test1()
    {
        x = "b";
    }
    public static void main(String[] args) 
    {
           System.out.println(new Test1().x);  //#2
    }
}

[William P O'Sullivan]

#2
then
#1
#1
#1

...

ad infinitum (well, until Stack overflows)

WP

[Janki Shah]

Understood the point. Thank you William.