[jira] [Commented] (YARN-505) NPE at AsyncDispatcher$GenericEventHandler
[
https://issues.apache.org/jira/browse/YARN-505?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14395456#comment-14395456
]
Junping Du commented on YARN-505:
-
We should never handle null event for AsyncDispatcher, and this is a basic
assumption for every call of handle(event) on AsyncDispatcher in YARN. We do
have such a practice that: we don't check null if this object is not supposed
to be null. If it (become null) do happen in some situations, then we fix these
situations because that is not we expect. In this case, NPE is a warn for us
that something unexpected happens. I will resolve this JIRA as won't fix.
NPE at AsyncDispatcher$GenericEventHandler
--
Key: YARN-505
URL: https://issues.apache.org/jira/browse/YARN-505
Project: Hadoop YARN
Issue Type: Improvement
Components: resourcemanager
Affects Versions: 3.0.0
Reporter: Przemyslaw Pretki
Priority: Minor
Steps to reproduce:
{code}
@Test
public void testAsyncDispatcher()
{
AsyncDispatcher dispatcher = new AsyncDispatcher();
EventHandler handler = dispatcher.getEventHandler();
handler.handle(null);
}
{code}
Moreover, event taken from *BlockingQueue* will never be *null*, so that it
seems that the following condition is not necessary
(AsyncDispatcher.createThread() method):
{code}
if (event != null) {
dispatch(event);
}
{code}
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[jira] [Commented] (YARN-505) NPE at AsyncDispatcher$GenericEventHandler
[
https://issues.apache.org/jira/browse/YARN-505?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13674208#comment-13674208
]
Niranjan Singh commented on YARN-505:
-
The NPE is in the LinkedBlockingQueue class of JDK.
In handler.handle(null), the event which is null in this case is put in
LinkedBlockingQueue ,
without checking whether the event is null or not.
eventQueue.put(event);line 188 of org.apache.hadoop.yarn.event.AsyncDispatcher.
One solution could be to check for null when event is put in eventQueue below.
if(event != null){
eventQueue.put(event);
}else{
LOG.warn(Event cannot be null+event);
}
NPE at AsyncDispatcher$GenericEventHandler
--
Key: YARN-505
URL: https://issues.apache.org/jira/browse/YARN-505
Project: Hadoop YARN
Issue Type: Improvement
Components: resourcemanager
Affects Versions: 3.0.0
Reporter: Przemyslaw Pretki
Priority: Minor
Steps to reproduce:
{code}
@Test
public void testAsyncDispatcher()
{
AsyncDispatcher dispatcher = new AsyncDispatcher();
EventHandler handler = dispatcher.getEventHandler();
handler.handle(null);
}
{code}
Moreover, event taken from *BlockingQueue* will never be *null*, so that it
seems that the following condition is not necessary
(AsyncDispatcher.createThread() method):
{code}
if (event != null) {
dispatch(event);
}
{code}
--
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