Solved

ConcurrentModificationException while using addAll method

Posted on 2009-05-13
13
355 Views
Last Modified: 2012-05-06
                 these loop will read the values from the form and put it in requestList.
                  
                  for (int i = 1; i <= 1; i++) {
                         cdtls= new ContainerDetails();
                         cdtls.setContainerType(request.getParameter("ContainerType_"+i+"_1"));
                         cdtls.setContainerNumber(request.getParameter("ContainerNumber_"+i+"_2"));
                         cdtls.setContainerDesc(request.getParameter("ContainerDescription_"+i+"_3"));
                         AL.add(cdtls);
                  }

                         ArrayList requestList=al;

                        //this list will give me first 10 records for the particular booking id;

                         ArrayList dataBaseList =DAO.getDBDetails(bookingId);

                  
                  ArrayList addList= new ArrayList();
                  addList.add("10");

                  // compared the addList number versus the dataBaseList ContainerDetails object id, if both r
                  same then first i need to remove that id from dataBaseList and then add requestList to dataBaseList.
                  i am getting java.util.ConcurrentModificationException while doing addAll method.
                  whats wrong with this code?

                  if(addList != null && !addList.get(0).equals("") && addList.size() > 0)
                        {
                              for (Iterator iterator = addList.iterator(); iterator.hasNext();) {
                                    String addId = (String) iterator.next();
                                    
                                    for (Iterator iterator2 = dataBaseList.iterator(); iterator2
                                                .hasNext();) {
                                          ContainerDetails object = (ContainerDetails) iterator2.next();
                                    
                                          if(object.getId() == Integer.parseInt(addId))
                                          {
                                                iterator2.remove();
                                                dataBaseList.addAll(al);
            
                                          }

                              }
                           }
                        }
0
Comment
Question by:chaitu chaitu
  • 4
  • 4
  • 2
  • +2
13 Comments
 
LVL 12

Expert Comment

by:Gibu George
Comment Utility
Are you using Threads in the application
0
 
LVL 20

Author Comment

by:chaitu chaitu
Comment Utility
no
0
 
LVL 12

Expert Comment

by:Gibu George
Comment Utility
What type of application is this is it a web application?
0
 
LVL 20

Author Comment

by:chaitu chaitu
Comment Utility
yes
0
 
LVL 86

Expert Comment

by:CEHJ
Comment Utility
The first loop will only execute once, is that your intention?
0
 
LVL 86

Accepted Solution

by:
CEHJ earned 500 total points
Comment Utility
You can't addAll to dataBaseList while you're iterating it. Try instead:
        if(addList != null && !addList.get(0).equals("") && addList.size() > 0)

        {

            List temp = new ArrayList();

            for (Iterator iterator = addList.iterator(); iterator.hasNext();) {

                String addId = (String) iterator.next();
 

                for (Iterator iterator2 = dataBaseList.iterator(); iterator2

                        .hasNext();) {

                    ContainerDetails object = (ContainerDetails) iterator2.next();
 

                    if(object.getId() == Integer.parseInt(addId))

                    {   

                        iterator2.remove();

                        //dataBaseList.addAll(al);

                        temp.addAll(al);
 

                    }
 

                }   

            }   

            if (temp.size() > 0)

            {

                dataBaseList.addAll(temp);

            }

        }

Open in new window

0
Why You Should Analyze Threat Actor TTPs

After years of analyzing threat actor behavior, it’s become clear that at any given time there are specific tactics, techniques, and procedures (TTPs) that are particularly prevalent. By analyzing and understanding these TTPs, you can dramatically enhance your security program.

 
LVL 92

Expert Comment

by:objects
Comment Utility
why not use a Map (keyed on id), that way you would not even need to loop at all.
using the appropriate data structure can greatly simplify your code

0
 
LVL 5

Expert Comment

by:avya2k
Comment Utility
As per specifications, you can not modify contents while iterating a collection
Instead collect all contents in temparory list and add it to main list after iteration
0
 
LVL 20

Author Comment

by:chaitu chaitu
Comment Utility
objects,

can you give me some hint what you are trying to tell?
0
 
LVL 92

Expert Comment

by:objects
Comment Utility
for example if you had a map keyed on id you would not need to loop through every element looking for a particular id.

0
 
LVL 86

Expert Comment

by:CEHJ
Comment Utility
>>Instead collect all contents in temparory list and add it to main list after iteration

(which is what happens in the code i posted)

chaituu, what result do you get when you run that?
0
 
LVL 20

Author Comment

by:chaitu chaitu
Comment Utility
CEHJ,

ur solution is working.i thought i am doing some unwanted code thats why i am taking objects suggestion.
0
 
LVL 86

Expert Comment

by:CEHJ
Comment Utility
:-)
0

Featured Post

Free Trending Threat Insights Every Day

Enhance your security with threat intelligence from the web. Get trending threat insights on hackers, exploits, and suspicious IP addresses delivered to your inbox with our free Cyber Daily.

Join & Write a Comment

For customizing the look of your lightweight component and making it look lucid like it was made of glass. Or: how to make your component more Apple-ish ;) This tip assumes your component to be of rectangular shape and completely opaque. (COD…
After being asked a question last year, I went into one of my moods where I did some research and code just for the fun and learning of it all.  Subsequently, from this journey, I put together this article on "Range Searching Using Visual Basic.NET …
Viewers will learn about the different types of variables in Java and how to declare them. Decide the type of variable desired: Put the keyword corresponding to the type of variable in front of the variable name: Use the equal sign to assign a v…
This tutorial explains how to use the VisualVM tool for the Java platform application. This video goes into detail on the Threads, Sampler, and Profiler tabs.

763 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

9 Experts available now in Live!

Get 1:1 Help Now