CODEWITHSUNDEEP
java
DarshilShah305
DarshilShah305

Reputation: 23

Creating Hashset object in method decreases the stack memory in java

I have read that only primitives are stored in Stack memory and objects are stored in Heap memory. In the following program I am recursively calling a method to check the maximum stack size before stackoverflow error occurs.

public class MaxStackSize {
static int i =0;
public static void main(String[] args) {
    method1();
}

public static void method1()
{
    i++;
    System.out.println(i);
    method1();
}
}

Here the max output for 'i' is 53481.

If I add HashSet object to the method and populate it:

public class MaxStackSize {
static int i =0;
public static void main(String[] args) {
    method1();
}
public static void method1()
{
    HashSet<String> set = new HashSet<String>();
    set.add("one");
    set.add("two");
    set.add("three");
    set.add("four");
    set.add("five");
    set.add("six");
    set.add("seven");
    set.add("eight");
    set.add("nine");

    i++;
    System.out.println(i);
    method1();
}
}

The max output for 'i' is 25403.

For both the cases VM arg is -Xss5m.

If only primitives are stored on stack why does the stacksize decrease when object of HashSet is created.

Upvotes: 2

Views: 304

Answers (1)

Jim Garrison
Jim Garrison

Reputation: 86774

Primitives are stored on the stack. So are local variables which are object references. The HashSet you instantiate goes on the heap but the reference to each HashSet, variable set, goes on the stack.

Upvotes: 2

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