Why am i getting StackOverflowError?

[Vinay Belagavi]

 
1. public class InstanceTest
2. {
3.int a=20;
4.public InstanceTest()
5.{
6.InstanceTest it1 = new InstanceTest();
7.System.out.println(it1.a);
8.}
9.public static void main(String[] ars)
10.{
11.InstanceTest it = new InstanceTest();
12.System.out.println(it.a);
13.}
14. }

When I compile and run the program, I get a StackOverflowError.I am not able to understand the reason.

Is it because I have created an instance of the class in the constructor?The program works fine if line 6 and 7 are removed.

The documentation says that

stack overflow occurs because an application recurses too deeply

.
what do you mean by application recurses too deeply?

Can anybody explain this to me.

I am breaking my head over this

[Simeon Cherniy]

You call:
InstanceTest it = new InstanceTest(); -> constructor called
InstanceTest it1 = new InstanceTest(); -> constructor called
...
Recursion.
Too deeply means that ideally this recursion is infinite

[Watsh Rajneesh]

Stack overflow happens as you are calling the constructor (new InstanceTest()) within the constructor body - and this makes it a recursive function.

The function calls are stored on the stack of the process (jvm's process' stack memory). When a function is called, its return address and local vars/references are kept on the top of the stack. If this function calls another function (or itself - as in recursion) then the stack size grows to accomodate the new function's info. When there is no exit criteria specified for a recursion (as in your case) the functions keep adding to the top of the stack and there comes a time when stack size reaches the maximum possible size and the JVM process balks out complaining an overflow.

[Vinay Belagavi]

Thanks Simeon and Rajneesh,

Itz all clear now