🚀 go-pugleaf

Hi i have an array of strings that that has to be returned to an
appletclass.
unfortunately i m getting a nullpointerexception.
i dont know why
here is the code of the method that returns the array and the calling code
of the applet

public String[] getOutOfStockItems(){
    int itemsOOS = 0;
    for(int i = 0; i < it.length;i++)
       if(it[i].getQuantity() < 1)
          itemsOOS += 1;

    osi = new String[itemsOOS];

    for(int i = 0; i < it.length; i++)
       if(it[i].getQuantity() < 1)
          osi[i] = it[i].getName();
    return osi;
 }

Calling code
if (e.getSource()==bt_reorder){
String[] array = Stock.getOutOfStockItems();
for(int i = 0; i<array.length; i++){
  tf_reorder.setText(tf_reorder.getText()+" "+array[i]);
 }
}
Help given will be appreciated.