java. Lang. stackoverflowerror Why do I get stackoverflow exception here

I have a list of parent and child items displayed in a hierarchy I want to switch their extended property Therefore, if you click a parent and its children are displayed, all parent children are collapsed, and vice versa

The stackoverflow trace points to this row

if (childItem.getItemId() == item.getItemId()) {
    hideItemAndDescendants(childItem); //causing stack overflow
  }

I think a stack overflow occurs when a method keeps calling it indefinitely But in this case, I have a for loop, which only iterates through the item list. The size of the list is only about 10

public boolean toggleNodeCollapseState(long itemId) {
        boolean changed = false; // a flag to determine if anything collapsed or expanded
         for (int i = 0; i < items.size(); i++) {
            Item childItem = items.get(i);
            if (childItem.getParentItemId() == itemId) {
                changed = true;
                childItem.setCollapsed(!childItem.isCollapsed());

                if (childItem.isCollapsed()) {
                    hideItemAndDescendants(childItem);
                } else {
                    showDescendants(childItem);
                }

            }
         }
        return changed;
    }

    public void hideItemAndDescendants(Item item) {
        item.hide();
        for (int i = 0; i < items.size(); i++) {
            Item childItem = items.get(i);
            if (childItem.getItemId() == item.getItemId()) {
                  hideItemAndDescendants(childItem);
            }
        }
    }

    public void showDescendants(Item item) {
        item.hide();
        for (int i = 0; i < items.size(); i++) {
            Item childItem = items.get(i);
            if (childItem.getItemId() == item.getItemId()) {
                childItem.show();
                if (!childItem.isCollapsed()) {
                    showDescendants(childItem);
                }
            }
        }
    }

Solution

You have a recursive call in hideitemandcalendars:

for (int i = 0; i < items.size(); i++) {
    Item childItem = items.get(i);
    if (childItem.getItemId() == item.getItemId()) {
          hideItemAndDescendants(childItem);
    }
}

Therefore, if childitem getItemId()== item. Getitemid(), then call hideitemanddescendants (childitem); Again This may result in an infinite loop, resulting in stackoverflowexception