java.lang.IndexOutOfBoundsException occuring on ArrayList

Question

CopyOnWriteArrayList<Options> Options= new CopyOnWriteArrayList<Options>();
Options Options = Options.get(selectedFilterIndex);

I am getting the error in the above line. The Options is an ArrayList. I tried with ArrayList as well as CopyOnWriteArrayList, but get the below error. How handle such exceptions.

06-21 15:28:23.257: E/XXX(8985): Uncaught exception is: 
06-21 15:28:23.257: E/XXX(8985): java.lang.RuntimeException: An error occured while executing doInBackground()
06-21 15:28:23.257: E/XXX(8985):  at android.os.AsyncTask$3.done(AsyncTask.java:278)
06-21 15:28:23.257: E/XXX(8985):  at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
06-21 15:28:23.257: E/XXX(8985):  at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
06-21 15:28:23.257: E/XXX(8985):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
06-21 15:28:23.257: E/XXX(8985):  at java.util.concurrent.FutureTask.run(FutureTask.java:137)
06-21 15:28:23.257: E/XXX(8985):  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
06-21 15:28:23.257: E/XXX(8985):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
06-21 15:28:23.257: E/XXX(8985):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
06-21 15:28:23.257: E/XXX(8985):  at java.lang.Thread.run(Thread.java:856)
06-21 15:28:23.257: E/XXX(8985): Caused by: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
06-21 15:28:23.257: E/XXX(8985):  at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:251)
06-21 15:28:23.257: E/XXX(8985):  at java.util.ArrayList.get(ArrayList.java:304)
06-21 15:28:23.257: E/XXX(8985):  at com.usercontext.CommonActivity$6.doInBackground(AppointmentsActivity5.java:354)
06-21 15:28:23.257: E/XXX(8985):  at com.usercontext.CommonActivity$6.doInBackground(AppointmentsActivity5.java:1)
06-21 15:28:23.257: E/XXX(8985):  at android.os.AsyncTask$2.call(AsyncTask.java:264)
06-21 15:28:23.257: E/XXX(8985):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)

did you check for selectedFilterIndex <= options.size(). I think selectedFilterIndex is growing and becomes greater than options.size(). — Vaibhav Raj
– Vaibhav Raj, Commented Jun 21, 2013 at 10:23
@VaibhavRaj It is not, since options.size() is 0. The list is empty. — Maroun
– Maroun, Commented Jun 21, 2013 at 10:23
Then, its obvious that you will get this error. Since, your list is of size zero and you are trying to access an index grater than 0. — Vaibhav Raj
– Vaibhav Raj, Commented Jun 21, 2013 at 10:25

Jon Skeet · Accepted Answer · 2013-06-21 10:22:57Z

5

You shouldn't be handling this exception - you should be writing code that isn't going to cause it in the first place.

You've just created an empty list - there's no value you can pass to get which will return a value. The list has a size of 0, and the index is meant to be greater than or equal to 0, and strictly less than the size.

Additionally, your code would be much simpler to read if you followed the Java naming conventions of making variables camelCased - that will avoid having the same name for both a variable and a type. Also avoid using the same variable name twice...

CopyOnWriteArrayList<Options> allOptions = new CopyOnWriteArrayList<Options>();
// This will still fail for any value of selectedFilterIndex, as the list
// is empty... but at least it's easier to understand.
Options selectedOptions = allOptions.get(selectedFilterIndex);

answered Jun 21, 2013 at 10:22

Jon Skeet

1.5m893 gold badges9.3k silver badges9.3k bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Community · Accepted Answer · 2020-06-20 09:12:55Z

1

You have just declared the List , there are no elements in it yet .

CopyOnWriteArrayList<Options> Options= new CopyOnWriteArrayList<Options>();

And you are trying to get() from the List with no elements . ArrayList internally will use an array buffer to store elements . According to the Javadoc get(int index):

Throws:

IndexOutOfBoundsException - if the index is out of range (index < 0 || index >= size())

Hence Options.get(selectedFilterIndex); will work only for (selectedFilterIndex>-1 && selectedFilterIndex < Options.size())

edited Jun 20, 2020 at 9:12

CommunityBot

11 silver badge

answered Jun 21, 2013 at 10:22

AllTooSir

49.5k17 gold badges132 silver badges164 bronze badges

1 Comment

Maroun Over a year ago

You might want to advise following Java naming conventions.

Collectives™ on Stack Overflow

java.lang.IndexOutOfBoundsException occuring on ArrayList

2 Answers 2

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related