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https://issues.apache.org/jira/browse/GIRAPH-125?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13188331#comment-13188331
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Avery Ching commented on GIRAPH-125:
------------------------------------

Thanks for findings this.  I agree this is a bug.  I know that it is small, but 
do you mind making a patch?  Then I can commit it on your behalf.
                
> Bug in LongDoubleFloatDoubleVertex.sendMsgToAllEdges()
> ------------------------------------------------------
>
>                 Key: GIRAPH-125
>                 URL: https://issues.apache.org/jira/browse/GIRAPH-125
>             Project: Giraph
>          Issue Type: Bug
>          Components: graph
>    Affects Versions: 0.1.0
>            Reporter: Yuanyuan Tian
>   Original Estimate: 5m
>  Remaining Estimate: 5m
>
> I just found a bug in the sendMsgToAllEdges() function of the 
> LongDoubleFloatDoubleVertex class. The segment of the code that contains the 
> bug is:
>         final LongWritable destVertex = new LongWritable();
>         final MutableVertex<LongWritable, DoubleWritable, FloatWritable,
>             DoubleWritable> vertex = this;
>         verticesWithEdgeValues.forEachKey(new LongProcedure() {
>             @Override
>             public boolean apply(long destVertexId) {
>                 destVertex.set(destVertexId);
>                 vertex.sendMsg(destVertex, msg);
>                 return true;
>             }
>         });
> Here destVertex is a final object, but this single object is reused in the 
> forEachKey function many times. Each time its actual value is changed but the 
> same object is put to the underlying message list (a hashmap) through 
> vertex.sendMsg. Because the single destVertex object has been put into the 
> underlying hashmap again and again, destVertex.set(destVertexId) will change 
> the existing keys in the hashmap. Eventually, every keys added to the hash 
> map will have the same value as the last key. 
> A simple fix is as follows:
>         final MutableVertex<LongWritable, DoubleWritable, FloatWritable,
>             DoubleWritable> vertex = this;
>         verticesWithEdgeValues.forEachKey(new LongProcedure() {
>             @Override
>             public boolean apply(long destVertexId) {
>                 vertex.sendMsg(new LongWritable(destVertexId), msg);
>                 return true;
>             }
>         });

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