concurrentmodification

I get an error on the following line. I'm doing the process of adding to the jsonarray. Please help me. jsonArr=new JSONArray(); if(req.getSession().getAttribute("userses")!=null){ String name=(req.getParameter("name")==null?"":to_EnglishName(req.getParameter("name").toUpperCase())); if(!name.equals("")){ for(Book c:GlobalObjects.bookList){ if(c.getBookName().startsWith(name)){ jsonObjec=new JSONObject(); jsonObjec.put("label",c.getBookName()); jsonObjec.put("value", c.getId()); jsonArr.add(jsonObjec);//java.util.ConcurrentModificationException } } } } jsonArr.write(res.getWriter()); This is

This question already has an answer here: Why is a ConcurrentModificationException thrown and how to debug it 6 answers The following Java code throws a ConcurrentModificationException , as expected: public class Evil { public static void main(String[] args) { Collection<String> c = new ArrayList<String>(); c.add("lalala"); c.add("sososo"); c.add("ahaaha"); removeLalala(c); System.err.println(c); } private static void removeLalala(Collection<String> c) { for (Iterator<String> i = c.iterator(); i.hasNext();) { String s = i.next(); if(s.equals("lalala")) { c.remove(s); } } } } But the following

This question already has an answer here: Why is a ConcurrentModificationException thrown and how to debug it 6 answers I was reading about ConcurrentModificationException and how to avoid it. Found an article . The first listing in that article had code similar to the following, which would apparently cause the exception: List<String> myList = new ArrayList<String>(); myList.add("January"); myList.add("February"); myList.add("March"); Iterator<String> it = myList.iterator(); while(it.hasNext()) { String item = it.next(); if("February".equals(item)) { myList.remove(item); } } for (String item

This question already has an answer here: Iterating through a Collection, avoiding ConcurrentModificationException when removing objects in a loop 23 answers If I modify a Collection while iterating over it using for-each loop, it gives ConcurrentModificationException . Is there any workaround? Use Iterator#remove . This is the only safe way to modify a collection during iteration. For more information, see The Collection Interface tutorial. If you also need the ability to add elements while iterating, use a ListIterator . One work around is to save your changes and add/remove them after the