Making stackoverflow deliberately

Question

The following code make a stackoverflow error:

int f(){  
    return f();  
}

But are there any other ways to make a stackoverflow error?
(Thanks in advance)

You understand why the stack overflows? – Thorbjørn Ravn Andersen Sep 19 '18 at 14:58 — Thorbjørn Ravn Andersen, Sep 19 '18 at 14:58
`class A { A a = new A(); }`. – Andy Turner Sep 19 '18 at 15:00 — Andy Turner, Sep 19 '18 at 15:00
@Thor, I think I know it – abolfazl-sh Sep 19 '18 at 15:22 — abolfazl-sh, Sep 19 '18 at 15:22

dustytrash · Answer 1 · 2018-09-19T15:35:16.377

2

Here's another way to throw a StackOverflowError, without overflowing the stack:

int f()
{
    throw new StackOverflowError();
}

Another way is to have a method call another method, which calls that method The following will produce a StackOverflowError:

public static void main(String[] args)
{
    testMethod();
}

public static void testMethod()
{
    testMethod2();
}

public static void testMethod2()
{
    testMethod();
}

In theory you might be able reduce the stack size (e.g -Xss1k) and try to overflow the stack by declaring too many primitive variables.

However the minimum stack size I can set is 70k. Otherwise I get the error The stack size specified is too small, Specify at least 108k (error doesn't appear between 80k - 107k+, though)

edited Sep 19 '18 at 15:35

answered Sep 19 '18 at 15:00

dustytrash

1,568
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I am searching for another way to make a lot variable – abolfazl-sh Sep 19 '18 at 15:03
That's faking it, not making it :-) – Sergey Kalinichenko Sep 19 '18 at 15:03
@Abolfazl-sh Java does not allocate arrays on the stack, so it would take too many variables to overflow the stack on a single go (see [this Q&A](https://stackoverflow.com/q/12961559/335858) for additional information). – Sergey Kalinichenko Sep 19 '18 at 15:05
@dasblinkenlight You could change the JVM stack size to something much smaller – dustytrash Sep 19 '18 at 15:09
hey, I am searching another way(except recursive methods) to do this – abolfazl-sh Sep 19 '18 at 15:10
@Abolfazl-sh I edited my answer to include non-recursive method – dustytrash Sep 19 '18 at 15:36

Sven Affeld · Answer 2 · 2018-09-20T10:09:40.257

0

Any recursive method will generate an overflow error, if recursive depth is large (or deep?) enough. Your method is the perfect example, as it will generate unlimited depth.

There is no other way that I am aware of that doesn't include recursion and which is practically possible.

If you declare an Array that is too large, you will get an OutOfMemoryError, because the Array is not stored on the Stack but the Heap.

Local variables take up Stack space, but you cannot declare so many local variables (e.g. int i1 = 1; int i2 = 2; ... int i99999 = 99999; ...), because you are limited to 65536 characters.

You could try to "manually" call too many methods, e.g. int f1() { return f2(); } int f2(){ return f3();} ... but that would be basically the same as doing the recursion that you already mentioned.

Opening too many Threads also won't work, as each Thread is assigned it's own Stack. You will only get an OutOfMemoryError like with the Array.

edited Sep 20 '18 at 10:09

answered Sep 19 '18 at 15:00

Sven Affeld

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just recursive methods make this problem, nothing else? – abolfazl-sh Sep 19 '18 at 15:04
No, not only recursive methods. Whenever a method or any line of code calls another method, a small packet of information is put on top of the stack until the program returns back to where it left. With recursive methods, this pile of packets, i.e. the "Stack", can grow very quickly until it "overflows". – Sven Affeld Sep 19 '18 at 15:08
ok , but if it's possible bring some code to do it(except recursive methods) thanks – abolfazl-sh Sep 19 '18 at 15:15

Making stackoverflow deliberately

2 Answers2