recursion - Java Recursive Method ArrayList is not adding all child elements to the final ArrayList -

i writing recursive method traverse hierarchy of java objects. purpose wrote recursive method takes root node(parent) parameter. here base method calls recursive method traverse:

if (category.id == gallerie_id_test) {                 traverse(category);                 system.out.println("children ...." + subcategories);             } 

and in traverse method wrote logic traverses child nodes of parent node. when add child objects arraylist, children not getting added final list method. returning child count of parent node need child nodes of subsequent nodes too.

here code goes:

private static void traverse(kalturacategory category)         throws kalturaapiexception {     list<kalturacategory> subcategories = new arraylist<kalturacategory>();     kalturacategorylistresponse categorieslist = null;     if (category != null && category.directsubcategoriescount >= 1) {         kalturacategoryfilter filter = new kalturacategoryfilter();         filter.parentidequal = category.id;         categorieslist = getcategorieslist(filter);         if (categorieslist.totalcount != 0) {             (kalturacategory subcat : categorieslist.objects) {                 traverse(subcat);                 subcategories.add(subcat);             }         }         system.out.println("subcategories size ------>"                 + subcategories.size());      }  } 

my output is:

subcategories size ------>3 subcategories size ------>4 subcategories size ------>5 subcategories size ------>5 subcategories size ------>1 subcategories size ------>6 children ....[] 

but want separate child objects 1 arraylist , return first method. please me resolving this. in advance.

the reason recursion getting copy of array , return nothing original parent array [pass value].

try moving category list outside function , make global/static variable.