Hi Benjamin,
Does your vertex class have a publicly accessible no-arg constructor?
That's implicitly required because each Vertex class implements Writable.
If you want to use to have a look at your code, you could maybe put it
on github?
Best,
Sebastian
On 02.03.2012 20:51, Benjamin Heitmann wrote:
> Hello,
>
> in the last week I started working with Apache Giraph. My goal is to
> implement a version of the
> spreading activation algorithm (as described on Wikipedia [1] and in this
> article [2] ).
> Using Giraph will hopefully allow scaling for Linked Data/RDF from DBPedia.
>
> I used the ConnectedComponentsVertex Example (and its UnitTest) as the
> starting point for my own Vertex, TextInputFormat, TextOutputFormat and
> UnitTest (and a class for VertexData/State).
> In addition, I ensured that the ConnectedComponentsVertexTest runs
> successfully, both from the giraph source tree
> and from my own project.
>
> My Vertex class is called SpreadingActivationVertex, and it directly extends
> BasicVertex, and it has the following <I, V, E, M> signature:
> public abstract class SpreadingActivationVertex extends
> BasicVertex<IntWritable, SpreadingActivationStateWritable, NullWritable,
> DoubleWritable>
> As you can see, I need to maintain more then one variable for the state of
> the vertex,
> and I need to pass doubles as messages.
>
> When I execute my UnitTest, I get the following error:
>
> 59820 [Thread-4] WARN org.apache.hadoop.mapred.LocalJobRunner -
> job_local_0001
> java.lang.RuntimeException: java.lang.InstantiationException
> at
> org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:115)
> at org.apache.giraph.graph.BspUtils.createVertex(BspUtils.java:365)
> at
> ie.deri.uimr.ld_sa.prototyping.giraph.SpreadingActivationTextInputFormat$SpreadingActivationVertexReader.getCurrentVertex(SpreadingActivationTextInputFormat.java:53)
> at
> org.apache.giraph.graph.BspServiceWorker.readVerticesFromInputSplit(BspServiceWorker.java:440)
> at
> org.apache.giraph.graph.BspServiceWorker.loadVerticesFromInputSplit(BspServiceWorker.java:371)
> at
> org.apache.giraph.graph.BspServiceWorker.loadVertices(BspServiceWorker.java:305)
> at
> org.apache.giraph.graph.BspServiceWorker.setup(BspServiceWorker.java:583)
> at org.apache.giraph.graph.GraphMapper.setup(GraphMapper.java:474)
> at org.apache.giraph.graph.GraphMapper.run(GraphMapper.java:646)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:763)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:369)
> at
> org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:210)
> Caused by: java.lang.InstantiationException
> at
> sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:30)
> at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
> at
> org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:113)
> ... 11 more
>
>
> Using the eclipse debugger, I traced it to these lines of code in Hadoop:
>
> org.apache.hadoop.util.ReflectionUtils, line 113 in newInstance():
>
> try {
> Constructor<T> meth = (Constructor<T>) CONSTRUCTOR_CACHE.get(theClass);
> if (meth == null) {
> meth = theClass.getDeclaredConstructor(EMPTY_ARRAY);
> meth.setAccessible(true);
> CONSTRUCTOR_CACHE.put(theClass, meth);
> }
> result = meth.newInstance(); // <<<------------ this is the line
> causing the error
> } catch (Exception e) {
> throw new RuntimeException(e);
> }
>
> The constructor cache does not contain my vertex class, however the next
> lines successfully find the right constructor and put it into "meth".
> However, the invocation of meth.newInstance() fails with the above error.
>
>
> Did somebody have this error before ?
> What did I miss ?
> The class itself is successfully found, so it is not an issue of setting some
> paths.
> However getting a newInstance seems to fail for some reason.
>
> Would it be helpful if I provide the code for my 5 classes somewhere ? If
> yes, in which way would that be convenient for this mailing list ?
>
>
>
> [1] https://en.wikipedia.org/wiki/Spreading_activation
> [2] http://linkinghub.elsevier.com/retrieve/pii/0306457387900173
>
