How to use multithreading for getting WhereUsed Objects?

Hi, 

I have a list of parts and I want to get WhereUsed objects of them. As the data is very big , its taking too long time. so I want to implement multi threading .

This is my  code : 

for(WTPart part:setofparts)
    {
     /*ArrayList<Object> objectsList=new ArrayList<>();
     objectsList.add(new HashSet<String>());
     objectsList.add(new HashSet<String>());
     objectsList.add(new ArrayList<String>());
     
     getPartStructure(part, objectsList);    
     dataMap.put(part, objectsList);*/

}

 private   static ArrayList<Object> getPartStructure(WTPart part,ArrayList<Object> objectList )
 {
  try
  {  
   ArrayList<String> set=new ArrayList<>();
    QueryResult resultWhere=StructHelper.service.navigateUsedBy(part.getMaster(),true);  
   
   while (resultWhere.hasMoreElements())
   {
    Object object = (Object) resultWhere.nextElement();  
    if(object instanceof WTPart)
    { 
     WTPart prt=(WTPart) object;
     prt=(WTPart) VersionControlHelper.service.allIterationsOf(prt.getMaster()).nextElement();     
     if(!set.contains(prt.getNumber()))
     {
      set.add(prt.getNumber());
      if(prt.isEndItem())
      {
       String vehicleFamily=getIBAValue(prt,"VehicleFamily_Abbreviation");
       if(vehicleFamily!=null && !vehicleFamily.equals(""))
       {
        HashSet<String>familyList=(HashSet<String>)objectList.get(0);
        familyList.add(vehicleFamily);
       }
       else
       {
        HashSet<String>UndisclosedFamilyList=(HashSet<String>)objectList.get(1);
        UndisclosedFamilyList.add(prt.getNumber());
       }
       ArrayList<String>list=(ArrayList<String>)objectList.get(2);
       list.add(prt.getNumber()+" "+vehicleFamily);
      }else{
      getPartStructure(prt,objectList);
      }
     }
    }
   }
  }catch (Exception ex)
  {
   ex.printStackTrace();
  }
  return objectList;
 }